Wisconsin State Tax Guide
Click your state on the map to see filing deadlines, extension rules, refund tracking, and payment options for that state. States shown in gray are coming soon.
Hover or tab a state to see its name.
Wisconsin State Tax Guide
Wisconsin Key deadlines (tax year 2025, return filed in 2026)
- Filing deadline: Apr 15, 2026
- Extension request deadline: Apr 15, 2026
- Extended return deadline: Oct 15, 2026 (6-month extension)
- Payment deadline: Apr 15, 2026
- Differs from federal: No
If 90% of the tax owed isn't paid by the unextended due date, additional penalties and delinquent interest can apply
If the due date for filing your return falls on a. Saturday, Sunday, or legal holiday, your return is due by the next regular working day.
October 15, 2026 (6-month extension)
Relevant Links
Payment rules
If 90% of the tax owed isn't paid by the unextended due date, additional penalties and delinquent interest can apply
Payment options
Payment plan availability
Available: Yes
Filing forms
Regular filing
- IRS Form 4868
Extension
- Wisconsin Form 1-ES - estimated payment voucher · Download form
Wisconsin Refund Tracking
Do I need to file?
Wisconsin does not require taxpayers to file a separate state extension request. If you receive a federal filing extension by submitting IRS Form 4868, Wisconsin automatically honors that extension for your state return as well. There is no need to send a copy of the federal extension to the state before the original filing deadline. When you file your Wisconsin income tax return, simply attach a copy of your approved federal extension or include a copy of Form 4868 showing only your identifying information and signature. If you owe taxes: You must submit your estimated payment voucher (Wisconsin Form 1-ES) by the original April deadline
Filing methods
Online filing
Via federal form 4868
Mail filing
If you owe a balance Form 1-ES
