Quartli — Quarterly Tax Estimator

Wisconsin Quarterly Estimated Taxes (2026)

Yes — self-employed workers in Wisconsin owe quarterly estimated taxes at both the federal and state level. You pay the IRS four times a year (April 15, June 15, September 15, January 15), and Wisconsin expects state estimated payments on its own schedule, which for most filers mirrors the federal dates. For 2026 planning, Quartli uses 5.3% — the Wisconsin marginal rate for a single filer with about $100k of taxable income under the official 2026 brackets. Your exact rate depends on income, filing status, and state-specific deductions.

Example: freelancer earning $80,000 in Wisconsin

A single filer with $80,000 of net self-employment income in 2026 (standard deduction, QBI deduction per Form 8995):

Federal self-employment tax$11,304
Federal income tax$5,344
Federal quarterly payment$4,162
Wisconsin state quarterly (≈5.3% planning rate)≈$1,060

Federal figures computed with official 2026 IRS brackets (Rev. Proc. 2025-32). The Wisconsin figure is a flat-rate planning approximation.

2026 quarterly due dates

QuarterIncome periodFederal due date
Q1Jan 1 – Mar 31, 2026April 15, 2026
Q2Apr 1 – May 31, 2026June 15, 2026
Q3Jun 1 – Aug 31, 2026September 15, 2026
Q4Sep 1 – Dec 31, 2026January 15, 2027

CPA-prepared Wisconsin estimate

A licensed CPA prepares your personalized Wisconsin state estimate — actual brackets, deductions, and credits, delivered by email within 48 hours, for a one-time $29. Available at quartli.com.

Frequently asked questions

Does Wisconsin require quarterly estimated tax payments?

Yes. If you're self-employed in Wisconsin, you generally owe BOTH federal quarterly estimated taxes (to the IRS) and Wisconsin state estimated taxes (to the state revenue agency). The federal due dates are April 15, June 15, September 15, and January 15.

What is the Wisconsin income tax rate for 2026?

For planning purposes, Quartli uses 5.3% for Wisconsin — the 2026 marginal rate for a single filer with roughly $100,000 of taxable income, per the state's official 2026 brackets. Your actual rate depends on your income level, filing status, and Wisconsin-specific deductions and credits — a CPA-prepared estimate accounts for all of these.

When are quarterly estimated taxes due in Wisconsin in 2026?

Federal deadlines apply everywhere: April 15, 2026 (Q1), June 15, 2026 (Q2), September 15, 2026 (Q3), and January 15, 2027 (Q4). Most states, including Wisconsin, follow the same schedule for state estimated payments, but always confirm with the state revenue agency.

How do I calculate my quarterly taxes as a freelancer in Wisconsin?

Start with the federal side: self-employment tax (15.3% on 92.35% of net earnings) plus federal income tax, divided into four payments. Quartli's free calculator does this instantly using official 2026 IRS figures. For the Wisconsin state portion, Quartli offers a CPA-prepared state estimate for $29.

Reviewed by Lena Hanna, CPA · Last updated June 2026 · Federal figures per IRS Rev. Proc. 2025-32; state planning rates per the official 2026 state brackets as compiled by the Tax Foundation.

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