Your return is due May 17, 2021.
If you can't file on time, you can get an extension. You may use any federal extension provision for Wisconsin, even if you're filing your federal return by May 17th.
How to get an extension:
You don't need to submit a separate request for an extension to the department prior to the time you file your Wisconsin return. When you file your Form 1, enclose either:
- a copy of your federal extension application (for example, Form 4868) or
- a statement indicating which federal extension provision you want to apply for Wisconsin (for example, the federal automatic 2-month extension for citizens living outside the United States).
An extension only extends the deadline to file your return. If you expect to owe taxes to Wisconsin, you'll need to pay that amount by May 17, 2021, to avoid penalties and interest. You can mail a check or money order with a completed Wisconsin Form 1-ES
or pay by credit card on the Official Payments