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Wisconsin Watch partners with Gigafact to produce fact briefs — bite-sized fact checks of trending claims. Read our methodology to learn how we check claims.


The Republican leader of the Wisconsin Senate recently proposed a flat tax that would reap annual savings for millionaires in excess of $100,000.

The proposal would gradually reduce income tax rates until 2026, when a single rate of 3.25% would apply. Wisconsin currently has four brackets: 3.54%, 4.65%, 5.3% and 7.65%.

The Legislative Fiscal Bureau said those making $1 million or more would save an average of $112,167 in 2026. The median tax filer making between $60,000 and $70,000 would get an average tax decrease of $690.

Under the plan, Wisconsin’s income tax revenue would drop by $2 billion in the 2023-24 tax year and $5 billion annually by 2026-27, the LFB said.

Gov. Tony Evers, who supports a progressive tax system, has vowed to veto the proposal.

Fourteen states have or are implementing a flat tax, the Tax Foundation reported in November.

In more than a century of state income taxes, only four states have ever transitioned from a graduated-rate income tax to a flat tax. Another four adopted legislation doing so in 2022, and a planned transition in a fifth state is now going forward under a recent court decision.

This Fact Brief is responsive to conversations such as this one.


PBS Wisconsin: LeMahieu proposes flat income tax rate for Wisconsin by 2026

State of Wisconsin | Department of Revenue: Tax Rates

Legislative Fiscal Bureau: Individual Income Tax Four-Year Phase-In of 3.25% Tax Rate

AP News: Wisconsin Gov. Evers opposes GOP flat income tax cut plan

Tax Foundation: States Inaugurate a Flat Tax Revolution

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Tom Kertscher joined as a Wisconsin Watch fact checker in January 2023 and contributes to our collaboration with the The Gigafact Project to fight misinformation online. Kertscher is a former longtime newspaper reporter, including at the Milwaukee Journal Sentinel, who has worked as a self-employed journalist since 2019. His gigs include contributing writer for PolitiFact and sports freelancer for The Associated Press.