Side-by-side tax comparison between Illinois (4.95% top rate, flat) and Wisconsin (7.65% top rate, graduated). See which state lets you keep more at every salary level, and how cost of living changes the picture.
Illinois uses a flat income tax (4.95% flat) while Wisconsin has a graduated system (3.5-7.65%). On a $100K salary, Illinois takes $4,950 in state and local taxes compared to Wisconsin’s $4,973 \u2014 a difference of $23.
Because Illinois has flat brackets while Wisconsin is graduated, the gap between them changes at different income levels. Illinois’s flat rate is predictable, while Wisconsin’s graduated brackets may benefit lower earners but penalize higher incomes.
Illinois wins at 10 out of 10 salary levels tested. The advantage exists but is modest across the income spectrum.
| Salary | Illinois | Wisconsin | Difference | Winner |
|---|---|---|---|---|
| $40K | $32,340 | $32,331 | −$9 | Illinois |
| $50K | $39,880 | $39,869 | −$11 | Illinois |
| $60K | $47,420 | $47,407 | −$14 | Illinois |
| $75K | $57,825 | $57,808 | −$17 | Illinois |
| $100K | $74,175 | $74,153 | −$23 | Illinois |
| $120K | $87,255 | $87,228 | −$27 | Illinois |
| $150K | $106,326 | $106,292 | −$34 | Illinois |
| $200K | $138,987 | $138,942 | −$45 | Illinois |
| $250K | $170,889 | $170,833 | −$56 | Illinois |
| $300K | $200,479 | $200,411 | −$68 | Illinois |
Take-home pay only tells part of the story. Illinois has a cost of living index of 93 while Wisconsin is at 93 (national average = 100).
With similar costs of living (93 vs 93), the tax difference is the primary factor. What you see in raw take-home pay is essentially what you get in purchasing power: $79,758 in Illinois vs $79,734 in Wisconsin.
For a single earner at $100K filing jointly, take-home becomes $79,760 in Illinois and $79,738 in Wisconsin \u2014 a difference of $23. The gap remains similar regardless of filing status.
On paper, moving from Wisconsin to Illinois would save $23/year on a $100K salary, or $113 over 5 years. But relocation involves real costs: moving expenses, potentially buying/selling a home, changing jobs, and adjusting to a new community.
At $23/year, the tax difference alone likely isn’t worth relocating for. Other factors — job market, lifestyle, family — should drive the decision. The tax savings are a nice bonus if you’re already considering the move for other reasons.