Side-by-side tax comparison between Hawaii (11% top rate, graduated) and Idaho (5.3% top rate, flat). See which state lets you keep more at every salary level, and how cost of living changes the picture.
Hawaii uses a graduated income tax (1.4-11%) while Idaho has a flat system (5.3% flat). On a $100K salary, Hawaii takes $7,150 in state and local taxes compared to Idaho’s $5,300 \u2014 a difference of $1,850.
Because Hawaii has graduated brackets while Idaho is flat, the gap between them changes at different income levels. Hawaii’s rates increase with income, so high earners feel the difference more acutely.
Idaho wins at 10 out of 10 salary levels tested. The advantage exists but is modest across the income spectrum.
| Salary | Hawaii | Idaho | Difference | Winner |
|---|---|---|---|---|
| $40K | $31,460 | $32,200 | +$740 | Idaho |
| $50K | $38,780 | $39,705 | +$925 | Idaho |
| $60K | $46,100 | $47,210 | +$1,110 | Idaho |
| $75K | $56,175 | $57,563 | +$1,388 | Idaho |
| $100K | $71,975 | $73,825 | +$1,850 | Idaho |
| $120K | $84,615 | $86,835 | +$2,220 | Idaho |
| $150K | $103,026 | $105,801 | +$2,775 | Idaho |
| $200K | $134,587 | $138,287 | +$3,700 | Idaho |
| $250K | $165,389 | $170,014 | +$4,625 | Idaho |
| $300K | $193,879 | $199,429 | +$5,550 | Idaho |
Take-home pay only tells part of the story. Hawaii has a cost of living index of 192 while Idaho is at 95 (national average = 100).
This is a substantial difference. After adjusting for cost of living, $100K in Hawaii has purchasing power of $37,487 compared to $77,711 in Idaho. Idaho wins on both raw take-home and cost-adjusted purchasing power, making it the clear winner for a $100K earner.
For a single earner at $100K filing jointly, take-home becomes $77,560 in Hawaii and $79,410 in Idaho \u2014 a difference of $1,850. The gap remains similar regardless of filing status.
On paper, moving from Hawaii to Idaho would save $1,850/year on a $100K salary, or $9,250 over 5 years. But relocation involves real costs: moving expenses, potentially buying/selling a home, changing jobs, and adjusting to a new community.
At $1,850/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.