Wisconsin Nonprofit Tax Deadlines 2026
Complete guide to Nonprofit filing dates, extensions, estimated payment schedules, and required forms in Wisconsin for the 2026 tax year. Wisconsin imposes a state income tax, so Nonprofit entities must file both federal and state returns.
Wisconsin Nonprofit filing deadline
Nonprofit annual return generally due the 15th day of the 5th month.
Due: May 15, 2026
Extension: Nov 15, 2026
Form: State nonprofit return
Estimated payments
No state estimated payment schedule listed.
Due: N/A
Wisconsin Nonprofit Tax Calendar at a Glance
| Event | Date |
|---|---|
| Filing deadline | May 15, 2026 |
| Extension deadline | Nov 15, 2026 |
FAQ
When is the Nonprofit tax filing deadline in Wisconsin for 2026?
The Wisconsin Nonprofit tax return is due May 15, 2026 for the 2026 tax year. An extension is available until Nov 15, 2026.
Does Wisconsin require Nonprofit estimated tax payments?
Estimated payments are not typically required at the entity level for Nonprofit in Wisconsin, but confirm with Wisconsin Department of Revenue.
What form do I file for a Nonprofit in Wisconsin?
Nonprofit entities in Wisconsin file using Form State nonprofit return. You can download the form from Wisconsin Department of Revenue at https://www.revenue.wi.gov.
Can I get an extension for my Wisconsin Nonprofit tax return?
Yes. Wisconsin allows an extension for Nonprofit returns until Nov 15, 2026. Note that an extension gives you more time to file, not more time to pay — any tax owed is still due by the original deadline of May 15, 2026.
What are the penalties for filing late in Wisconsin?
Wisconsin typically charges a failure-to-file penalty (usually 5% of unpaid tax per month, up to 25%) and a failure-to-pay penalty (usually 0.5-1% per month). Interest also accrues on unpaid balances. Filing for an extension by the original deadline avoids the failure-to-file penalty but not the failure-to-pay penalty.
Where can I file Wisconsin Nonprofit taxes?
File through Wisconsin Department of Revenue. Visit https://www.revenue.wi.gov for e-filing options, downloadable forms, and payment portals.
Wisconsin Estimated Tax Payments
View the full quarterly estimated payment schedule for Wisconsin, including all entity types and payment methods.
View Wisconsin estimated payments →