State estimated tax — 2026
Who has to make Wisconsin quarterly estimated payments, the 2026 due-date calendar, the safe-harbor rules that avoid an underpayment penalty, and how to pay through Quick Pay.
Wisconsin requires Form 1-ES payments once you expect to owe $500 or more of net 2026 tax after subtracting withholding and credits, and your withholding won’t cover the smaller of the safe-harbor tests below.
| Installment | % of annual estimate | Due date | Note |
|---|---|---|---|
| Q1 | 25% | April 15, 2026 | — |
| Q2 | 25% | June 15, 2026 | — |
| Q3 | 25% | September 15, 2026 | — |
| Q4 | 25% | January 15, 2027 | — |
Wisconsin divides the required annual payment into four equal 25% installments; if your requirement first arises later in the year, the schedule compresses (half by June 15 if you start after March 31, three-quarters by September 15 if you start after May 31, or the full amount by January 15 if you start after August 31). Farmers and fishermen (at least two-thirds of gross income from farming or fishing) can skip estimated payments entirely by paying their full 2026 tax by January 15, 2027, or by filing and paying their complete return by March 1, 2027.
Wisconsin sidesteps underpayment interest once your payments cover whichever amount is least: 90% of what your 2026 tax turns out to be, your full 2025 liability (available only when that prior return spanned a complete twelve months, and off the table for estates or trusts carrying $20,000 or more of 2026 taxable income), or 90% figured by annualizing your income as it actually arrives. Every filer runs through that same math regardless of income — Wisconsin never asks a higher earner for a bigger slice of last year’s bill, unlike the AGI-triggered add-on used in Minnesota, Indiana or Michigan.
Estimate your annual Wisconsin tax, test it against the safe harbor above, then split the required annual payment across the installments in the calendar. The site's quarterly planner handles the math and the federal side together.
Pay online through Quick Pay, or mail a check or money order with the Form 1-ES voucher. Wisconsin requires electronic payment of estimated tax once your total estimated tax payments in the prior year were $2,000 or more (Wis. Admin. Code §Tax 1.12(4)(a)11.) — the Department must first notify you the mandate applies, and a hardship waiver is available on Form EFT-102.
Wisconsin charges a flat 12% annual underpayment interest rate (Wis. Stat. §§71.03, 71.09, 71.64; Wis. Admin. Code §Tax 2.04) — among the highest fixed rates of any state, computed as days-late ÷ 365 × 12% × the underpayment. A 2025 bill (AB1026) that would have tied the rate to the federal funds rate starting in 2026 failed to pass, so the fixed 12% figure remains current law.
See the Wisconsin 2026 tax brackets for current rates, or the Wisconsin state tax calculator to estimate your full-year liability.
The four Wisconsin due dates for 2026 are April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. Wisconsin divides the required annual payment into four equal 25% installments; if your requirement first arises later in the year, the schedule compresses (half by June 15 if you start after March 31, three-quarters by September 15 if you start after May 31, or the full amount by January 15 if you start after August 31). Farmers and fishermen (at least two-thirds of gross income from farming or fishing) can skip estimated payments entirely by paying their full 2026 tax by January 15, 2027, or by filing and paying their complete return by March 1, 2027.
No. A Wisconsin filer earning $4 million clears the same 90%-of-current-year or 100%-of-prior-year comparison as one earning $40,000 — nothing in the calculation changes once a taxpayer crosses a particular income line.
Wisconsin sets its underpayment interest rate as a fixed 12% by statute (Wis. Stat. §71.09) rather than tying it to a floating benchmark like the bank prime rate or federal short-term rate, which is what keeps most other states’ rates lower and variable. A 2025 bill that would have switched Wisconsin to a federal-funds-rate-indexed rate starting 2026 failed to pass.
It can. Filers 67 or older can subtract up to $24,000 ($48,000 married filing jointly) of qualified retirement income starting with tax year 2025, but anyone claiming that subtraction may not claim any other Wisconsin tax credit on the same return — which changes your required-annual-payment math if you were counting on a credit you can no longer use.
Pay online through Quick Pay, or mail a check with the Form 1-ES voucher. Wisconsin requires electronic payment of estimated tax once your total estimated tax payments in the prior year were $2,000 or more (Wis. Admin. Code §Tax 1.12(4)(a)11.) — the Department must first notify you the mandate applies, and a hardship waiver is available on Form EFT-102.
Compare how Wisconsin stacks up against the other states with a Rising search trend for estimated-tax rules.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Due dates, safe harbor, and how to pay.
Use these guides for rule explanations, planning context, and follow-up questions beyond the calculator result.
Four installments (4/15, 6/15, 9/15, 1/15), safe harbor 90%/100%
Form 2210 safe harbor, 90%/100% prior-year test, 7% rate
State-specific quarterly payments, safe harbor by state
Form 1040-ES Q1 through Q4 payment dates, covered income periods, and quarter-specific planning guides