States take two approaches to income tax: flat rates (one percentage for everyone) and graduated brackets (higher rates on higher income). As of 2026, 13 states use a flat tax: Arizona (2.5%), Colorado (4.4%), Georgia (5.19%), Idaho (5.3%), Illinois (4.95%), Indiana (2.95%), Iowa (3.8%), Kentucky (3.5%), Michigan (4.25%), North Carolina (3.99%), Ohio (2.75%), Pennsylvania (3.07%), and Utah (4.65%). The remaining states with income taxes use graduated systems.
At $50,000 income, flat-tax states often look competitive. Illinois charges a flat $2,475 (4.95%). Compare that to California, where graduated brackets yield roughly $1,580 on the same income — California’s lower brackets actually protect low earners. New York charges about $2,650 at $50K. At this income level, graduated systems with low starting brackets beat most flat-tax states.
At $200,000, the picture flips dramatically. Illinois still charges 4.95% — $9,900 total. But California’s graduated brackets push the effective rate to roughly 7.8%, costing $15,600. New York hits about $12,800. Oregon charges around $17,600 at its 9.9% top rate. High earners save thousands in flat-tax states, which is exactly why flat-tax proponents advocate for them.
The distributional impact is clear: flat taxes are regressive in practice. A worker earning $35,000 in Illinois pays the same 4.95% rate as someone earning $500,000 — that’s $1,732 vs $24,750. Both rates are identical, but the burden falls much harder on the lower earner relative to their ability to pay. Graduated systems like California’s charge as little as 1% on the first $10,412, softening the blow for modest incomes.
Some states have tried to split the difference. Arizona flattened its tax from graduated brackets to a single 2.5% rate in 2023, giving high earners a massive cut while modestly reducing rates for everyone else. Georgia moved to a 5.19% flat rate in 2024. Iowa switched from graduated brackets to a flat 3.8% in 2026. Ohio flattened to 2.75% in 2026. The trend toward flat taxes has accelerated, with supporters arguing simplicity and critics arguing regressivity.
For your personal decision, the math is straightforward: if you earn under $60,000, graduated-tax states with low bottom brackets generally charge you less. If you earn over $120,000, flat-tax states almost always save you money — and the savings grow proportionally with income. Use our calculator to compare your exact tax burden across all 50 states and see which system works best for your salary.