Understanding Wisconsin's Tax Extension Policy

Automatic Extension with Federal Approval

Wisconsin automatically grants a six-month extension to file your state income tax return if you've obtained a federal extension by filing IRS Form 4868. This means you don't need to submit a separate state extension form. Include your federal extension with your Wisconsin return.

Extension Deadlines

• Original Due Date: April 15th
• Extended Due Date: October 15th

Remember, this extension applies only to the filing deadline, not the payment deadline. Pay taxes owed by April 15th.

How to File for a Wisconsin Tax Extension

Step 1: File IRS Form 4868

Step 2: Attach Your Federal Extension to Your Wisconsin Return

Step 3: Pay What You Owe by April 15

Payment Options

Wisconsin offers several methods to pay your taxes:

• Online: Use the Wisconsin Department of Revenue's My Tax Account system.
• Credit Card: The state accepts payments via credit card.
• Mail: Send a check or money order with Form 1-ES to:

Wisconsin Department of Revenue

Special Circumstances

Military Personnel

If you're serving in a combat zone, Wisconsin extends your filing and payment deadlines. The extension lasts for at least 180 days after the last day you're in the combat zone.

In addition, those on duty in military or naval service who are not in a combat zone but stationed outside of the US or Puerto Rico, who are allowed an automatic 2-month federal extension, are automatically granted a WI extension.

Disaster Relief Extensions

If a federally declared disaster has hit you, you automatically get more time to file—no need to jump through extra hoops. Just follow the IRS guidelines and, when you file, pop a “03” in the Special Conditions box and jot down the name of the disaster on the line provided. Simple as that.

Penalties for Late Filing and Payment

Failing to file or pay by April 15th can result in penalties:

• Late Filing Fee: $50
• Interest on Unpaid Taxes: 1.5% per month. (Note: Wisconsin reduces the interest to 1% per month during the extension period.)
• Negligence Penalty: 5% per month of the tax owed based on the return, up to a maximum of 25%

Quick Peek at Wisconsin Tax Stats

Want to get a feel for the local tax vibe? Here’s what’s going on in the Badger State:

• Income Tax Rates: 3.50% to 7.65%, depending on your income bracket.
• Top Bracket: Kicks in at $420,420 for joint filers (2024 tax year)
• Returns Filed: Over 3 million per year—you're definitely not alone.

Bottom line? Filing on time (or obtaining an extension) is crucial, and e-filing is the preferred method.

Source: U.S. Census Bureau, via Federal Reserve Bank of St. Louis "State Tax Collections: Total Taxes for Wisconsin." Accessed June 5, 2025.

Frequently Asked Questions (FAQs)

Do I need to file a separate Wisconsin extension form?

No. Wisconsin automatically grants a six-month extension if you have an approved federal extension.

Does the extension apply to tax payments?

No. The extension is only for the filing deadline. You still need to pay your taxes on/before April 15th.

How do I pay my Wisconsin taxes?

You can pay online through the My Tax Account system, by credit card via ACI Payments, Inc., or by mailing a check with Form 1-ES.

What if I'm serving in a combat zone?

Wisconsin extends your filing and payment deadlines for at least 180 days after your service in the combat zone ends.

Final Thoughts: 

Wisconsin keeps it simple when it comes to tax extensions. As long as you file a federal extension by April 15th, you’re covered through October 15th.

Need a clear path to finish filing later? Our DIY-friendly software walks you through the process step by step.