Wisconsin Estimated Tax Payments 2026

Wisconsin’s test has two parts, and the instructions state both: you expect to owe at least $500 for 2026 after withholding and credits, and you expect your withholding to be less than the smallest of three amounts. The Department’s guidance document words the first part more briefly, as a balance due of $500 or more on your Wisconsin return.

• You must pay Wisconsin estimated tax for 2026 if you expect to owe at least $500 in tax for 2026 after withholding and credits and you expect your withholding to be less than the smallest of 90% of your 2026 tax, 100% of your 2025 tax (if the return covered 12 months), or 90% of your 2026 tax computed by annualizing your taxable income.

  “You must pay Wisconsin estimated tax for 2026 if you expect to owe, after subtracting your withholding and credits, at least $500 in tax for 2026 and you expect your withholding to be less than the smallest of (1) 90% of the tax shown on your 2026 income tax return, (2) 100% of the tax shown on your 2025 income tax return, assuming the return covered 12 months*, or (3) 90% of the tax shown on your 2026 income tax return, computed by annualizing your taxable income.”

• The 100% of 2025 tax comparison does not apply to estates or trusts that have 2026 taxable income of $20,000 or more.

  “*This does not apply to estates or trusts that have 2026 taxable income of $20,000 or more.”

• You do not have to pay estimated tax if you were a full-year resident of Wisconsin for 2025 and had no tax liability for that 12-month period.

  “You do not have to pay estimated tax if you were a full-year resident of Wisconsin for 2025 and you had no tax liability for that 12-month period.”

• Generally, you are required to make quarterly estimated income tax payments if you expect your Wisconsin return to show a balance due of $500 or more.

  “Generally, you are required to make quarterly estimated income tax payments if you expect your Wisconsin income tax return to show a balance due of $500 or more.”

The 2026 Estimated Income Tax Worksheet in the instructions starts from the Wisconsin income you expect in 2026, subtracts the standard deduction and exemptions, applies the rate schedules, subtracts credits, and then subtracts the Wisconsin tax withheld and expected to be withheld. If four installments are due, each is one quarter of the balance. It is a worksheet estimate, not an assessment of your actual tax.

• Generally, if you do not prepay at least 90% of your 2026 tax liability or 100% of your 2025 tax, whichever is smaller, you may be subject to interest on the underpayment amount.

  “Generally, if you do not prepay at least 90% of your 2026 tax liability or 100% of your 2025 tax, whichever is smaller, you may be subject to interest on the underpayment amount.”

• Worksheet line 9: if line 6 less line 8 is less than $500, you are not required to make estimated tax payments.

  “If line 6 less line 8 is less than $500, you are not required to make estimated tax payments.”

• Worksheet line 10: if four installments are due, enter in each column 1/4 of the amount on line 9.

  “If four installments are due, enter in each column 1/4 of the amount on line 9.”

• If you are unsure of your estimate, you may want to pay more than 90% of the amount you have shown on line 6.

  “If you are unsure of your estimate, you may want to pay more than 90% of the amount you have shown on line 6.”

If your requirement to pay estimated tax is met after March 31, the instructions give a later first payment date: if it is met before June 1, the first payment is June 15, 2026 (1/2 of the estimated tax due); after May 31 and before September 1, September 15, 2026 (3/4); after August 31, January 15, 2027 (all). Any remaining payments should be 1/4 of your required annual payment.

• If you file your 2026 return by January 31, 2027, pay the entire balance due, and did not owe estimated tax for the September 2026 or prior installment date, the payment with your return is treated as timely payment of the estimated tax due on January 15, 2027.

  “If you file your 2026 income tax return by January 31, 2027, pay the entire balance due, and did not owe estimated tax for the September 2026 or prior installment date, the payment with your return will be treated as timely payment of the estimated tax due on January 15, 2027.”

• If at least two-thirds of your gross income (joint gross income, if applicable) for 2025 or 2026 is from farming or fishing, you have two options (next two quotes).

  “If at least two-thirds of your gross income (joint gross income, if applicable) for 2025 or 2026 is from farming or fishing, you may:”

• Pay your 2026 estimated tax in full by January 15, 2027; or

  “Pay your 2026 estimated tax in full by January 15, 2027; or”

• File your 2026 income tax return on or before March 1, 2027, and pay the total tax due; in this case you need not make estimated tax payments for 2026.

  “File your 2026 income tax return on or before March 1, 2027, and pay the total tax due. In this case, you need not make estimated tax payments for 2026.”

• If your return is filed on a fiscal year basis, your due dates are the 15th day of the 4th, 6th and 9th months of your current fiscal year and the 1st month of the following fiscal year. The instructions add this note: if any due date falls on a Saturday, Sunday or legal holiday, use the next business day.

  “If your return is filed on a fiscal year basis, your due dates are the 15th day of the 4th, 6th, and 9th months of your current fiscal year, and the 1st month of the following fiscal year. Note: If any due date falls on a Saturday, Sunday, or legal holiday, use the next business day.”

You can pay online, by mail with a Form 1-ES voucher, or by completing and printing the Department’s interactive Form 1-ES voucher. The instructions call paying online at the Department’s site a free service; paying by credit card, Apple Pay or PayPal goes through the Department’s third-party payment processor, which charges a $1 transaction fee and a 2.25% processing fee.

• Include, but do not staple or attach, your check or money order with Form 1-ES, payable to the Wisconsin Department of Revenue, and mail it to the address shown on Form 1-ES.

  “Include, but do not staple or attach, your check or money order with Form 1-ES. Make your remittance payable to the Wisconsin Department of Revenue and mail to the address shown on Form 1-ES.”

• To pay online, go to tap.revenue.wi.gov/pay. The instructions call this a free service.

  “To pay online, go to the department's website at: tap.revenue.wi.gov/pay. This is a free service.”

• To pay by credit card, Apple Pay or PayPal, there will be a $1 transaction fee and a 2.25% processing fee charged for this service.

  “There will be a $1 transaction fee and a 2.25% processing fee charged for this service.”

• Payments can be made via Quick Pay or in My Tax Account.

  “Payments can be made via Quick Pay or in My Tax Account”

Official page: Wisconsin Department of Revenue: pay online (tap.revenue.wi.gov/pay). Form: Form 1-ES (Wisconsin Estimated Income Tax voucher).

Wisconsin charges interest, not a flat penalty, on an underpaid installment. You work it out on Wisconsin Schedule U when you file your 2026 return; the Schedule U instructions cover the exceptions.

• If you are required to pay estimated tax and you do not, or you underpay any installment, you are subject to interest on the underpayment amount when you file your 2026 return; Wisconsin Schedule U is used to compute it.

  “If you are required to pay estimated tax and you do not, or you underpay any installment, you are subject to interest on the underpayment amount when you file your 2026 return. Wisconsin Schedule U is used to compute the interest due.”

• Underpayment interest is computed separately for each installment due date, so you may owe it for an earlier installment even if you pay enough tax later to make up the underpayment.

  “Underpayment interest is computed separately for each installment due date. Therefore, you may owe underpayment interest for an earlier installment due date even if you pay enough tax later to make up the underpayment.”