Every state that charges a single flat tax rate on all income. Simple, predictable, and often lower than graduated states.
Flat-tax states charge one rate on all income regardless of how much you earn. This makes tax planning predictable — every additional dollar is taxed at the same rate. Currently, 14 states use a flat income tax, with rates ranging from 4.25% to 5.3%.
Arizona leads flat-tax states with the highest take-home on $100K at $76,625. The lowest flat-tax rate belongs to Arizona at 2.5%. Flat-tax states are generally simpler for taxpayers but can be more regressive — lower earners pay the same percentage as high earners.
| # | State | Tax Rate | Type | Take-Home | Monthly | Eff. Rate | Cost Index | Cost-Adj. |
|---|---|---|---|---|---|---|---|---|
| 1 | Arizona | 2.5% | Flat | $76,625 | $6,385 | 23.4% | 97 | $78,995 |
| 2 | Iowa | 3.8% | Flat | $75,325 | $6,277 | 24.7% | 89 | $84,635 |
| 3 | North Carolina | 3.99% | Flat | $75,135 | $6,261 | 24.9% | 95 | $79,089 |
| 4 | Ohio | 2.75% | Flat | $74,875 | $6,240 | 25.1% | 90 | $83,194 |
| 5 | Colorado | 4.4% | Flat | $74,725 | $6,227 | 25.3% | 105 | $71,167 |
| 6 | Indiana | 2.95% | Flat | $74,675 | $6,223 | 25.3% | 90 | $82,972 |
| 7 | Pennsylvania | 3.07% | Flat | $74,555 | $6,213 | 25.4% | 98 | $76,077 |
| 8 | Utah | 4.65% | Flat | $74,475 | $6,206 | 25.5% | 99 | $75,227 |
| 9 | Illinois | 4.95% | Flat | $74,175 | $6,181 | 25.8% | 93 | $79,758 |
| 10 | Kentucky | 3.5% | Flat | $74,125 | $6,177 | 25.9% | 90 | $82,361 |
| 11 | Massachusetts | 5% | Flat | $74,125 | $6,177 | 25.9% | 118 | $62,818 |
| 12 | Georgia | 5.19% | Flat | $73,935 | $6,161 | 26.1% | 93 | $79,500 |
| 13 | Idaho | 5.3% | Flat | $73,825 | $6,152 | 26.2% | 95 | $77,711 |
| 14 | Michigan | 4.25% | Flat | $73,375 | $6,115 | 26.6% | 91 | $80,632 |