Side-by-side tax comparison between Idaho (5.3% top rate, flat) and New Hampshire (no income tax). See which state lets you keep more at every salary level, and how cost of living changes the picture.
New Hampshire has no state income tax, while Idaho uses a flat system with rates of 5.3% flat. On a $100K salary, this creates a state tax difference of $5,300/year that New Hampshire residents simply don’t pay.
Idaho’s flat 5.3% rate means the gap scales linearly with income. At $200K, you’d save $10,600 by being in New Hampshire instead.
New Hampshire wins at 10 out of 10 salary levels tested. The advantage is consistent and significant across the income spectrum.
| Salary | Idaho | New Hampshire | Difference | Winner |
|---|---|---|---|---|
| $40K | $32,200 | $34,320 | +$2,120 | New Hampshire |
| $50K | $39,705 | $42,355 | +$2,650 | New Hampshire |
| $60K | $47,210 | $50,390 | +$3,180 | New Hampshire |
| $75K | $57,563 | $61,538 | +$3,975 | New Hampshire |
| $100K | $73,825 | $79,125 | +$5,300 | New Hampshire |
| $120K | $86,835 | $93,195 | +$6,360 | New Hampshire |
| $150K | $105,801 | $113,751 | +$7,950 | New Hampshire |
| $200K | $138,287 | $148,887 | +$10,600 | New Hampshire |
| $250K | $170,014 | $183,264 | +$13,250 | New Hampshire |
| $300K | $199,429 | $215,329 | +$15,900 | New Hampshire |
Take-home pay only tells part of the story. Idaho has a cost of living index of 95 while New Hampshire is at 108 (national average = 100).
The cost of living gap is moderate. After adjustment, $100K has purchasing power of $77,711 in Idaho vs $73,264 in New Hampshire. However, Idaho actually provides better purchasing power despite New Hampshire’s take-home advantage.
For a single earner at $100K filing jointly, take-home becomes $79,410 in Idaho and $84,710 in New Hampshire \u2014 a difference of $5,300. The gap remains similar regardless of filing status.
On paper, moving from Idaho to New Hampshire would save $5,300/year on a $100K salary, or $26,500 over 5 years. But relocation involves real costs: moving expenses, potentially buying/selling a home, changing jobs, and adjusting to a new community.
With an annual savings of $5,300, the tax difference alone is significant enough to justify a move for many people — especially if career opportunities are comparable. At higher salaries, the savings grow even larger: a $200K earner would save $10,600/year.