The majority of deadlines listed here are for Tax Year 2024. Some apply to upcoming Tax Years and some are IRS or Federal deadlines.
April 15, 2025
Tax Year 2024
Income Tax Return
Prepare and eFile an IRS (Due Date April 15, 2025) and Wisconsin State Income Tax Return (Due Date April 15, 2025) until October 15, 2025. -
eFileIT
April 15, 2025
2024 Income Tax Extension
October 15, 2025
Tax Year 2024
Income Tax Return after the April 15, 2025 Wisconsin Tax Extension
Last day to e-File a 2024 Wisconsin State Income Tax Return for Tax Extension Filers and late eFilers. You can
only e-File (to file by paper see below) Wisconsin Income Tax Return together with an IRS Tax Return.
eFileIT
October 15, 2025 via mail-in Forms.
Forms incl. Mailing Address are listed below.
Tax Year 2024
Income Tax Return after the April 15, 2025 Wisconsin Tax Extension
Deadline for taxpayers who got a WI Tax Extension to file their WI Income Tax Return by mail-in Forms - the Forms incl. mailing addresses are listed below - is October 15, 2025. (Optionally, the
eFileIT deadline is Oct. 15, 2025). Instructions on how to
only - without the IRS return -
prepare and file a Wisconsin State Income Tax Return on eFile.com.
Tax Amendment for all Tax Years
IRS Due Dates
IRS Tax Return, Extension, Amendment Deadlines
2024, 2025, etc.
Other State Tax Return, Extension, Amendment Deadlines
2024, 2025, etc.
IRS Federal Income Tax Return, Amendment, Extension Deadlines
April 15, 2028
2024 Wisconsin Income Tax Return Refund.
IRS Tax Return Refund Claim DeadlineThe last day to file - you will not face late filing penalties - and claim your 2024 Wisconsin Income Tax Return Refund. This deadline does not apply if you owe 2024 Income Taxes.