Side-by-side comparison of income tax, property tax, sales tax, capital gains, and retirement treatment between Idaho and Montana for tax year 2026. Use the calculator below to estimate how much you would save (or pay) after relocating.
| Tax | Idaho | Montana |
|---|---|---|
| State income tax (effective) | 5.80% | 5.90% |
| Long-term capital gains | 5.80% | 4.10% |
| Property tax (effective) | 0.67% | 0.74% |
| Combined sales tax | 6.20% | 0.00% |
| Retirement income | ss-exempt | partial-exempt |
| Income system | flat | progressive |
Idaho total tax
$21,106
Montana total tax
$21,115
Idaho state tax
$5,736
Montana state tax
$5,745
Difference
+$9
Montana costs more
As % of income
0.01%
Federal tax is identical in both columns and excluded from the difference. Numbers use 2026 IRS brackets, state effective rates, and the 3.8% NIIT where applicable.
Moving from Idaho to Montana would cost an extra $9 per year on this profile.
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