Wisconsin business filing dates, 2027

State-level due dates for businesses filing in Wisconsin. Every line links to the official page it came from, with the date that page was read. Where no official source has been verified, the line says so instead of showing a date.

Add to Google Calendar Add to Apple or Outlook Download .ics45 dated lines in the calendar file · sources last read 2026-09-23

Coverage · 4 of 6 fully dated

Income / franchise tax return3 dates · 1 not dated yet
Estimated tax4 dates
Withholding17 dates
Unemployment insurance4 dates
Sales and use tax17 dates
Annual reportnot dated yet

Income / franchise tax return

3 dates · 1 not dated yet

The annual return for the business’s tax year, and in franchise-tax states the report that keeps the entity in good standing. Which form and which date depend on the entity type and the tax year. Where the source grants an extension, it extends the time to file; the source says whether it also extends the time to pay.

Why no dates: Every date shown here is checked against its official source.

Obligation	Applies to	Due rule	2027 dates	Source · retrieved
Form 3 partnership returncalendar-year partnership Source text “Partnership returns are filed on Form 3 and are due on the 15th day of the 3rd month after the end of the taxable year.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “Any extension of time granted by federal law or by the IRS for filing a federal partnership return automatically extends the date for filing the corresponding Wisconsin return. A federal extension extends the due date of the Wisconsin return to the extended due date of the federal return, regardless of when the federal return is actually filed. Extensions of time to file federal partnership returns with the IRS include the following: • Automatic six-month extension from the original due date of the return (use federal Form 7004).”verbatim · revenue.wi.gov · retrieved 2026-09-23 “It is not necessary to pay the Wisconsin tax that is estimated to be due in order to receive an extension of time to file the partnership tax return (Form 3) or nonresident partners' composite income tax return (Form 1CNP). However, tax not paid by the original due date of the return is subject to interest of 1% per month during the extension period.”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toA partnership's Form 3 is due the 15th day of the 3rd month after its taxable year ends; a federal extension (Form 7004, six months) extends it to the federal extended due date, and a Wisconsin-only extension is also available. Tax not paid by the original due date bears interest during the extension, so the extension does not move payment.	Due ruleForm 3: 15th day of the 3rd month after the tax year endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Mar 15MonForm 3extended (Federal Form 7004): Sep 15 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdf (official source, opens in a new tab)retrieved 2026-09-23
Form 5S tax-option (S) corporation returncalendar-year S corporation Source text “• Form 5S – Tax-option (S) corporation franchise or income tax return o 15th day of 3rd month after end of taxable year”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toAn S corporation's Form 5S is due the 15th day of the 3rd month after its taxable year ends.	Due ruleForm 5S: 15th day of the 3rd month after the tax year endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Mar 15MonForm 5S State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdf (official source, opens in a new tab)retrieved 2026-09-23
Form 4 / Form 6 corporation franchise or income tax returncalendar-year C corporation Source text “• Form 4 and 6 – Corporation franchise or income tax return o 15th day of 4th month after end of taxable year o Fiscal year ending on June 30th – 15th day of 3rd month after end of fiscal taxable year”verbatim · revenue.wi.gov · retrieved 2026-09-23 “(2) Wisconsin-only extensions Wisconsin law provides an automatic extension of seven months or until the original due date of the corporation’s corresponding federal return, whichever is later.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “Any extension of time granted by federal law or by the IRS for filing a federal corporation tax return or exempt organization business tax return automatically extends the date for filing the corresponding Wisconsin return. A federal extension extends the due date of the Wisconsin return to 30 days after the extended due date of the federal return, regardless of when the federal return is actually filed.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “It is not necessary to pay the Wisconsin tax ("tax" includes economic development surcharge) that is estimated to be due in order to receive an extension of time to file the franchise or income tax return or the nonresident composite income tax return (Form 1CNS). However, an extension of time to file is not an extension of time to pay the tax.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “Form 4T – Business franchise or income tax return for exempt organizations taxable as corporations”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toA corporation's Form 4 or 6 is due the 15th day of the 4th month after its taxable year ends (June 30 year-ends have their own line). Exempt organizations taxable as corporations file Form 4T on a different date and are not dated here (the preparer attests the entity is not one). Wisconsin's automatic extension (seven months or the federal original due date, whichever is later) and a federal extension (30 days after the federal extended date) both depend on the federal return, so the extended date is not computed. Tax is still due by the original date.	Due ruleForm 4 / Form 6: 15th day of the 4th month after the tax year endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Apr 15ThuForm 4 / Form 6 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdf (official source, opens in a new tab)retrieved 2026-09-23
Form 4 / Form 6 (June 30 year-end)	Applies toA corporation with a June 30 fiscal year files Form 4 or 6 by the 15th day of the 3rd month after its year ends. Exempt organizations taxable as corporations file Form 4T on a different date and are not dated here (the preparer attests the entity is not one). Wisconsin's automatic extension (seven months or the federal original due date, whichever is later) and a federal extension (30 days after the federal extended date) both depend on the federal return, so the extended date is not computed. Tax is still due by the original date.	Due ruleUnsupported	2027 datesThe rule names no 2027 due date for any business it applies to.	Source · retrievedNo verified source on file

Estimated tax

4 dates

Installments paid during the year toward the year’s tax. Whether a business must pay them depends on its expected liability, which this page cannot know; the lines show when installments fall due for those who must.

Obligation	Applies to	Due rule	2027 dates	Source · retrieved
Corporate estimated tax and surchargecalendar-year S corporation or C corporation Source text “Payments are due by the 15th day of the 4th, 6th, 9th, and 12th months of the taxable year and, for corporations receiving extensions, by the 15th day of the 4th month after the end of the taxable year. Exception : For fiscal years beginning in April, the first estimated tax payment is due June 15.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “For fiscal years beginning in April, the first estimated tax payment is due June 15.”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toA corporation required to pay Wisconsin estimated tax pays by the 15th day of the 4th, 6th, 9th and 12th months of its taxable year. A corporation receiving an extension also pays by the 15th day of the 4th month after the year ends; the profile cannot say whether it has an extension, so that payment is not dated here. A fiscal year beginning in April (a March year-end) pays its first installment June 15 and is not covered here.	Due rule1st estimate: 15th day of the 4th month of the tax year; 2nd estimate: 15th day of the 6th month of the tax year; 3rd estimate: 15th day of the 9th month of the tax year; 4th estimate: 15th day of the 12th month of the tax yearA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Apr 15Thu1st estimate Jun 15Tue2nd estimate Sep 15Wed3rd estimate Dec 15Wed4th estimate State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/Pages/OnlineServices/voucher-corp-es.aspx (official source, opens in a new tab)retrieved 2026-09-23

Corporate estimated tax and surchargecalendar-year S corporation or C corporation

Source text

“Payments are due by the 15th day of the 4th, 6th, 9th, and 12th months of the taxable year and, for corporations receiving extensions, by the 15th day of the 4th month after the end of the taxable year. Exception : For fiscal years beginning in April, the first estimated tax payment is due June 15.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“For fiscal years beginning in April, the first estimated tax payment is due June 15.”verbatim · revenue.wi.gov · retrieved 2026-09-23

Applies toA corporation required to pay Wisconsin estimated tax pays by the 15th day of the 4th, 6th, 9th and 12th months of its taxable year. A corporation receiving an extension also pays by the 15th day of the 4th month after the year ends; the profile cannot say whether it has an extension, so that payment is not dated here. A fiscal year beginning in April (a March year-end) pays its first installment June 15 and is not covered here.

Due rule1st estimate: 15th day of the 4th month of the tax year; 2nd estimate: 15th day of the 6th month of the tax year; 3rd estimate: 15th day of the 9th month of the tax year; 4th estimate: 15th day of the 12th month of the tax yearA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Apr 15Thu1st estimate
Jun 15Tue2nd estimate
Sep 15Wed3rd estimate
Dec 15Wed4th estimate

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrievedrevenue.wi.gov/Pages/OnlineServices/voucher-corp-es.aspxretrieved 2026-09-23

Withholding

17 dates

Returns and deposits of income tax withheld from employees’ wages. The agency assigns each employer a deposit frequency, usually from its past liability, so the dates differ by frequency.

Obligation	Applies to	Due rule	2027 dates	Source · retrieved
Withholding deposit report (WT-6)quarterly withholding filer Source text “The employer's withholding tax deposit report is filed on Form WT-6. The due date depends on the filing frequency the department assigns to the employer: • Semi-monthly filers with reporting period 1st to 15th day of month – last day of that month • Semi-monthly filers with reporting period 16th day to end of month – 15th day of following month • Monthly and quarterly filers – last day of month after end of reporting period • Annual filers – no deposit report is required”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toBy assigned frequency: monthly and quarterly filers by the last day of the month after the period; annual filers file no deposit report. Semi-monthly filers are not dated here.	Due ruleWT-6: last day of the month after the quarter endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Feb 1MonWT-6 · moved from Sun Jan 31 Apr 30FriWT-6 Aug 2MonWT-6 · moved from Sat Jul 31 Nov 1MonWT-6 · moved from Sun Oct 31 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdf (official source, opens in a new tab)retrieved 2026-09-23
Withholding deposit report (WT-6)monthly withholding filer Source text “The employer's withholding tax deposit report is filed on Form WT-6. The due date depends on the filing frequency the department assigns to the employer: • Semi-monthly filers with reporting period 1st to 15th day of month – last day of that month • Semi-monthly filers with reporting period 16th day to end of month – 15th day of following month • Monthly and quarterly filers – last day of month after end of reporting period • Annual filers – no deposit report is required”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toBy assigned frequency: monthly and quarterly filers by the last day of the month after the period; annual filers file no deposit report. Semi-monthly filers are not dated here.	Due ruleWT-6: last day of the month after the month endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Feb 1MonWT-6 · moved from Sun Jan 31 Mar 1MonWT-6 · moved from Sun Feb 28 Mar 31WedWT-6 Apr 30FriWT-6 May 31MonWT-6 Jun 30WedWT-6 Aug 2MonWT-6 · moved from Sat Jul 31 Aug 31TueWT-6 Sep 30ThuWT-6 Nov 1MonWT-6 · moved from Sun Oct 31 Nov 30TueWT-6 Dec 31FriWT-6 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdf (official source, opens in a new tab)retrieved 2026-09-23
Annual withholding reconciliation (WT-7) Source text “The employer's annual reconciliation of income tax withheld is filed on Form WT-7 and is due on January 31 following the end of the calendar year.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “Employers may request a 30-day extension of time to file the annual reconciliation if they are able to demonstrate good cause and reason for the requested delay. If an extension is granted for the Form WT-7, it also applies to the corresponding wage statements and information returns.”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toAn employer the preparer attests withholds Wisconsin income tax files the annual reconciliation (Form WT-7) by January 31 after the calendar year. A 30-day extension (to March 2, or March 1 in a leap year) may be requested for good cause; it also covers the wage statements. A business that discontinues files within 30 days of discontinuing, not dated here.	Due ruleWT-7: January 31 of the year after the calendar year endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Feb 1MonWT-7 · moved from Sun Jan 31extended: Mar 2 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdf (official source, opens in a new tab)retrieved 2026-09-23

Withholding deposit report (WT-6)quarterly withholding filer

Source text

“The employer's withholding tax deposit report is filed on Form WT-6. The due date depends on the filing frequency the department assigns to the employer: • Semi-monthly filers with reporting period 1st to 15th day of month – last day of that month • Semi-monthly filers with reporting period 16th day to end of month – 15th day of following month • Monthly and quarterly filers – last day of month after end of reporting period • Annual filers – no deposit report is required”verbatim · revenue.wi.gov · retrieved 2026-09-23

Applies toBy assigned frequency: monthly and quarterly filers by the last day of the month after the period; annual filers file no deposit report. Semi-monthly filers are not dated here.

Due ruleWT-6: last day of the month after the quarter endsA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Feb 1MonWT-6 · moved from Sun Jan 31
Apr 30FriWT-6
Aug 2MonWT-6 · moved from Sat Jul 31
Nov 1MonWT-6 · moved from Sun Oct 31

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdfretrieved 2026-09-23

Withholding deposit report (WT-6)monthly withholding filer

Source text

“The employer's withholding tax deposit report is filed on Form WT-6. The due date depends on the filing frequency the department assigns to the employer: • Semi-monthly filers with reporting period 1st to 15th day of month – last day of that month • Semi-monthly filers with reporting period 16th day to end of month – 15th day of following month • Monthly and quarterly filers – last day of month after end of reporting period • Annual filers – no deposit report is required”verbatim · revenue.wi.gov · retrieved 2026-09-23

Applies toBy assigned frequency: monthly and quarterly filers by the last day of the month after the period; annual filers file no deposit report. Semi-monthly filers are not dated here.

Due ruleWT-6: last day of the month after the month endsA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Feb 1MonWT-6 · moved from Sun Jan 31
Mar 1MonWT-6 · moved from Sun Feb 28
Mar 31WedWT-6
Apr 30FriWT-6
May 31MonWT-6
Jun 30WedWT-6
Aug 2MonWT-6 · moved from Sat Jul 31
Aug 31TueWT-6
Sep 30ThuWT-6
Nov 1MonWT-6 · moved from Sun Oct 31
Nov 30TueWT-6
Dec 31FriWT-6

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdfretrieved 2026-09-23

Annual withholding reconciliation (WT-7)

Source text

“The employer's annual reconciliation of income tax withheld is filed on Form WT-7 and is due on January 31 following the end of the calendar year.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“Employers may request a 30-day extension of time to file the annual reconciliation if they are able to demonstrate good cause and reason for the requested delay. If an extension is granted for the Form WT-7, it also applies to the corresponding wage statements and information returns.”verbatim · revenue.wi.gov · retrieved 2026-09-23

Applies toAn employer the preparer attests withholds Wisconsin income tax files the annual reconciliation (Form WT-7) by January 31 after the calendar year. A 30-day extension (to March 2, or March 1 in a leap year) may be requested for good cause; it also covers the wage statements. A business that discontinues files within 30 days of discontinuing, not dated here.

Due ruleWT-7: January 31 of the year after the calendar year endsA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Feb 1MonWT-7 · moved from Sun Jan 31extended: Mar 2

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdfretrieved 2026-09-23

Unemployment insurance

4 dates

Employer contribution and wage reports for unemployment insurance: the state program, and FUTA at the federal level.

Obligation	Applies to	Due rule	2027 dates	Source · retrieved
Quarterly contribution report Source text “Contribution reports are due by the close of the month following the end of the calendar quarter. Quarterly Due Dates The quarterly due dates are: 1st quarter (Jan., Feb., Mar.) due April 30 2nd quarter (Apr., May, June) due July 31 3rd quarter (July, Aug., Sept.) due October 31 4th quarter (Oct., Nov., Dec.) due January 31”verbatim · dwd.wisconsin.gov · retrieved 2026-09-23 “Due Dates Falling on Weekends or Holidays: Per DWD 110.07(4) the due date will be the next day that is not a Saturday, Sunday or legal holiday under state or federal law.”verbatim · dwd.wisconsin.gov · retrieved 2026-09-23	Applies toAn employer the preparer lists as a quarterly Wisconsin unemployment-insurance filer (subject to the Wisconsin UI law) files contribution reports by the close of the month after each quarter (April 30, July 31, October 31, January 31); a Saturday, Sunday or legal-holiday date moves to the next day that is none of those.	Due ruleContribution report: last day of the month after the quarter endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Feb 1MonContribution report · moved from Sun Jan 31 Apr 30FriContribution report Aug 2MonContribution report · moved from Sat Jul 31 Nov 1MonContribution report · moved from Sun Oct 31 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrieveddwd.wisconsin.gov/ui201/t4201.htm (official source, opens in a new tab)retrieved 2026-09-23

Quarterly contribution report

Source text

“Contribution reports are due by the close of the month following the end of the calendar quarter. Quarterly Due Dates The quarterly due dates are: 1st quarter (Jan., Feb., Mar.) due April 30 2nd quarter (Apr., May, June) due July 31 3rd quarter (July, Aug., Sept.) due October 31 4th quarter (Oct., Nov., Dec.) due January 31”verbatim · dwd.wisconsin.gov · retrieved 2026-09-23

“Due Dates Falling on Weekends or Holidays: Per DWD 110.07(4) the due date will be the next day that is not a Saturday, Sunday or legal holiday under state or federal law.”verbatim · dwd.wisconsin.gov · retrieved 2026-09-23

Applies toAn employer the preparer lists as a quarterly Wisconsin unemployment-insurance filer (subject to the Wisconsin UI law) files contribution reports by the close of the month after each quarter (April 30, July 31, October 31, January 31); a Saturday, Sunday or legal-holiday date moves to the next day that is none of those.

Due ruleContribution report: last day of the month after the quarter endsA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Feb 1MonContribution report · moved from Sun Jan 31
Apr 30FriContribution report
Aug 2MonContribution report · moved from Sat Jul 31
Nov 1MonContribution report · moved from Sun Oct 31

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrieveddwd.wisconsin.gov/ui201/t4201.htmretrieved 2026-09-23

Sales and use tax

17 dates

Returns for sales and use tax collected under a permit. The agency assigns each permit holder a filing frequency; the dates differ by frequency.

Obligation	Applies to	Due rule	2027 dates	Source · retrieved
Sales and use tax returnannual filer Source text “Returns must be filed by the last day of the month following the end of the reporting period, with one exception. Early monthly sales tax filers are required to file by the 20th of the month following the end of the reporting period.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “Example: An early monthly filer's February sales tax return is due March 20, rather than March 31.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “The department may grant you an additional month from the original due date of the return to file the return. The department will notify you if the extension is granted. However, if the tax is not paid by the original due date, the tax will be subject to 1% interest per month during the extension period and 1.5% interest per month thereafter.”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toA retailer the preparer attests is not an early monthly filer files returns by the last day of the month after the reporting period (monthly, quarterly or annual). Early monthly filers (due the 20th) are not covered here. The department may grant one more month to file on request; tax not paid by the original date bears interest.	Due ruleSales and use tax return: last day of the month after the calendar year endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Feb 1MonSales and use tax return · moved from Sun Jan 31extended: Mar 1 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/Pages/FAQS/pcs-sales.aspx (official source, opens in a new tab)retrieved 2026-09-23
Sales and use tax returnquarterly filer Source text “Returns must be filed by the last day of the month following the end of the reporting period, with one exception. Early monthly sales tax filers are required to file by the 20th of the month following the end of the reporting period.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “Example: An early monthly filer's February sales tax return is due March 20, rather than March 31.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “The department may grant you an additional month from the original due date of the return to file the return. The department will notify you if the extension is granted. However, if the tax is not paid by the original due date, the tax will be subject to 1% interest per month during the extension period and 1.5% interest per month thereafter.”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toA retailer the preparer attests is not an early monthly filer files returns by the last day of the month after the reporting period (monthly, quarterly or annual). Early monthly filers (due the 20th) are not covered here. The department may grant one more month to file on request; tax not paid by the original date bears interest.	Due ruleSales and use tax return: last day of the month after the quarter endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Feb 1MonSales and use tax return · moved from Sun Jan 31extended: Mar 1 Apr 30FriSales and use tax returnextended: May 31 Aug 2MonSales and use tax return · moved from Sat Jul 31extended: Aug 31 Nov 1MonSales and use tax return · moved from Sun Oct 31extended: Nov 30 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/Pages/FAQS/pcs-sales.aspx (official source, opens in a new tab)retrieved 2026-09-23
Sales and use tax returnmonthly filer Source text “Returns must be filed by the last day of the month following the end of the reporting period, with one exception. Early monthly sales tax filers are required to file by the 20th of the month following the end of the reporting period.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “Example: An early monthly filer's February sales tax return is due March 20, rather than March 31.”verbatim · revenue.wi.gov · retrieved 2026-09-23 “The department may grant you an additional month from the original due date of the return to file the return. The department will notify you if the extension is granted. However, if the tax is not paid by the original due date, the tax will be subject to 1% interest per month during the extension period and 1.5% interest per month thereafter.”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toA retailer the preparer attests is not an early monthly filer files returns by the last day of the month after the reporting period (monthly, quarterly or annual). Early monthly filers (due the 20th) are not covered here. The department may grant one more month to file on request; tax not paid by the original date bears interest.	Due ruleSales and use tax return: last day of the month after the month endsA date on a weekend moves to the next business day; state holidays are not compiled.	2027 dates Feb 1MonSales and use tax return · moved from Sun Jan 31extended: Mar 1 Mar 1MonSales and use tax return · moved from Sun Feb 28extended: Mar 29 Mar 31WedSales and use tax returnextended: Apr 30 Apr 30FriSales and use tax returnextended: May 31 May 31MonSales and use tax returnextended: Jun 30 Jun 30WedSales and use tax returnextended: Jul 30 Aug 2MonSales and use tax return · moved from Sat Jul 31extended: Aug 31 Aug 31TueSales and use tax returnextended: Sep 30 Sep 30ThuSales and use tax returnextended: Nov 1 Nov 1MonSales and use tax return · moved from Sun Oct 31extended: Nov 30 Nov 30TueSales and use tax returnextended: Dec 30 Dec 31FriSales and use tax returnextended: Jan 31 State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.	Source · retrievedrevenue.wi.gov/Pages/FAQS/pcs-sales.aspx (official source, opens in a new tab)retrieved 2026-09-23

Sales and use tax returnannual filer

Source text

“Returns must be filed by the last day of the month following the end of the reporting period, with one exception. Early monthly sales tax filers are required to file by the 20th of the month following the end of the reporting period.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“Example: An early monthly filer's February sales tax return is due March 20, rather than March 31.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“The department may grant you an additional month from the original due date of the return to file the return. The department will notify you if the extension is granted. However, if the tax is not paid by the original due date, the tax will be subject to 1% interest per month during the extension period and 1.5% interest per month thereafter.”verbatim · revenue.wi.gov · retrieved 2026-09-23

Applies toA retailer the preparer attests is not an early monthly filer files returns by the last day of the month after the reporting period (monthly, quarterly or annual). Early monthly filers (due the 20th) are not covered here. The department may grant one more month to file on request; tax not paid by the original date bears interest.

Due ruleSales and use tax return: last day of the month after the calendar year endsA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Feb 1MonSales and use tax return · moved from Sun Jan 31extended: Mar 1

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrievedrevenue.wi.gov/Pages/FAQS/pcs-sales.aspxretrieved 2026-09-23

Sales and use tax returnquarterly filer

Source text

“Returns must be filed by the last day of the month following the end of the reporting period, with one exception. Early monthly sales tax filers are required to file by the 20th of the month following the end of the reporting period.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“Example: An early monthly filer's February sales tax return is due March 20, rather than March 31.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“The department may grant you an additional month from the original due date of the return to file the return. The department will notify you if the extension is granted. However, if the tax is not paid by the original due date, the tax will be subject to 1% interest per month during the extension period and 1.5% interest per month thereafter.”verbatim · revenue.wi.gov · retrieved 2026-09-23

Due ruleSales and use tax return: last day of the month after the quarter endsA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Feb 1MonSales and use tax return · moved from Sun Jan 31extended: Mar 1
Apr 30FriSales and use tax returnextended: May 31
Aug 2MonSales and use tax return · moved from Sat Jul 31extended: Aug 31
Nov 1MonSales and use tax return · moved from Sun Oct 31extended: Nov 30

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrievedrevenue.wi.gov/Pages/FAQS/pcs-sales.aspxretrieved 2026-09-23

Sales and use tax returnmonthly filer

Source text

“Returns must be filed by the last day of the month following the end of the reporting period, with one exception. Early monthly sales tax filers are required to file by the 20th of the month following the end of the reporting period.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“Example: An early monthly filer's February sales tax return is due March 20, rather than March 31.”verbatim · revenue.wi.gov · retrieved 2026-09-23

“The department may grant you an additional month from the original due date of the return to file the return. The department will notify you if the extension is granted. However, if the tax is not paid by the original due date, the tax will be subject to 1% interest per month during the extension period and 1.5% interest per month thereafter.”verbatim · revenue.wi.gov · retrieved 2026-09-23

Due ruleSales and use tax return: last day of the month after the month endsA date on a weekend moves to the next business day; state holidays are not compiled.

2027 dates

Feb 1MonSales and use tax return · moved from Sun Jan 31extended: Mar 1
Mar 1MonSales and use tax return · moved from Sun Feb 28extended: Mar 29
Mar 31WedSales and use tax returnextended: Apr 30
Apr 30FriSales and use tax returnextended: May 31
May 31MonSales and use tax returnextended: Jun 30
Jun 30WedSales and use tax returnextended: Jul 30
Aug 2MonSales and use tax return · moved from Sat Jul 31extended: Aug 31
Aug 31TueSales and use tax returnextended: Sep 30
Sep 30ThuSales and use tax returnextended: Nov 1
Nov 1MonSales and use tax return · moved from Sun Oct 31extended: Nov 30
Nov 30TueSales and use tax returnextended: Dec 30
Dec 31FriSales and use tax returnextended: Jan 31

State legal holidays are not compiled: if this date is a state holiday, the deadline moves to the next business day.

Source · retrievedrevenue.wi.gov/Pages/FAQS/pcs-sales.aspxretrieved 2026-09-23

Annual report

Unsupported

The annual or biennial report an entity files with the Secretary of State (or its equivalent) to stay in good standing. Some are keyed to the month the entity was formed.

Why no dates: No official source confirmed yet for Wisconsin's annual report due date.

Obligation	Applies to	Due rule	2027 dates	Source · retrieved
Annual report	Applies toShown once verified	Due ruleUnsupported	2027 datesNo official source confirmed yet for Wisconsin's annual report due date.	Source · retrievedNo verified source on file

Due-date rules

no fixed date

The conventions other lines cite: how a date on a weekend or holiday moves, and how a disaster declaration postpones deadlines.

Obligation	Applies to	Due rule	2027 dates	Source · retrieved
Weekend and holiday due dates Source text “Note: If a due date falls on a Saturday, Sunday, or legal holiday, use the next business day.”verbatim · revenue.wi.gov · retrieved 2026-09-23	Applies toA Wisconsin Department of Revenue due date on a Saturday, Sunday or legal holiday moves to the next business day.	Due ruleNo date: see the source text	2027 dates—	Source · retrievedrevenue.wi.gov/DOR%20Publications/pb401.pdf (official source, opens in a new tab)retrieved 2026-09-23

Dates are computed from the linked pages as they read on each retrieval date. Agencies change their pages, and the IRS postpones deadlines after disasters; confirm with the source before filing.

Tracking these for a list of clients? FilingDates builds each client’s calendar from the same rules, with every date linked to its source.