FormPW-U: FormPW-U (2025)
Wisconsin · Wisconsin DOR · Used for tax years 2025
Wisconsin Form PW-U calculates underpayments of estimated withholding tax by pass-through entities and the related interest. It also calculates other interest and penalties and includes an annualized income installment worksheet. File it with Wisconsin Form PW-1.
Who files this form
Form PW-U is for pass-through entities to calculate underpayment of estimated withholding tax and related interest. The 2025 form says to file it with Wisconsin Form PW-1.
Complete Part II only if Form PW-1 is not filed by the unextended due date and shows withholding tax due. Complete Part III only if you use the annualized income installment method to calculate required installments.
When it's due
For tax year 2025, Part II, line 21 identifies the amount due on the 15th day of the month that includes the unextended due date, after the end of the taxable year.
The form does not print specific calendar dates for filing or estimated-payment installments. Line 5 refers to instructions for installment due dates, but those instructions are not available here.
What you'll need
Have these forms and records available to complete the 2025 Form PW-U:
- Wisconsin Form PW-1 for 2025, which must be filed with Form PW-U.
- Your 2024 Form PW-1, if applicable, for the prior year's withholding tax due.
- The entity's name and federal employer ID number.
- Records of 2025 withholding tax computed, tax withheld, estimated payments, and payment dates.
- If completing Part II, the Form PW-1 filing date, extension information, net withholding tax, and payments made.
- If using Part III, Wisconsin net income for each annualization period, adjustments, the applicable tax rate, and nonrefundable and refundable credits.
How to file
File Form PW-U with Wisconsin Form PW-1. The supplied form does not provide a mailing address or e-filing directions.
- Enter the total underpayment interest from Part I, line 17 on PW-1, line 9, unless the return is filed after the unextended due date and shows withholding tax due. In that case, enter it in Part II, line 22.
- Enter the total from Part II, line 26 on PW-1, line 10.
Common mistakes
Keep these printed directions in mind:
- Do not complete Part II unless Form PW-1 is filed after the unextended due date and shows withholding tax due.
- Complete Part III only when using the annualized income installment method. Finish one column through line 45 before starting the next column.
- Exclude estimated tax paid from refundable credits on Part III, line 35.
- On Part II, line 20, apply payments first to the 18%-per-year column.
Questions people ask
What interest rate does Part I use for underpayments?
Lines 15 and 16 use 12% per year, based on the amounts and number of days entered on the form.
Can I use the prior year's withholding tax to calculate required installments?
Line 4 says to use the smaller of line 2 or line 3 if the preceding taxable year's return covered 12 months. Otherwise, use line 2. Line 2 is 90% of the 2025 withholding tax due on line 1c, and line 3 is the 2024 withholding tax due from PW-1, if applicable.
When do I complete the annualized income worksheet?
Complete Part III only if you calculate required installments using the annualized income installment method.
What penalties does the form list for late filing?
If PW-1 is filed late without an extension or after the extended due date, line 25a calls for a penalty of 5% of the net tax due for each month or part of a month the return is late, up to 25%. Line 25b also calls for $50 or the applicable late fee.