Side-by-side comparison of income tax, property tax, sales tax, capital gains, and retirement treatment between Montana and Idaho for tax year 2026. Use the calculator below to estimate how much you would save (or pay) after relocating.
| Tax | Montana | Idaho |
|---|---|---|
| State income tax (effective) | 5.90% | 5.80% |
| Long-term capital gains | 4.10% | 5.80% |
| Property tax (effective) | 0.74% | 0.67% |
| Combined sales tax | 0.00% | 6.20% |
| Retirement income | partial-exempt | ss-exempt |
| Income system | progressive | flat |
Montana total tax
$21,115
Idaho total tax
$21,106
Montana state tax
$5,745
Idaho state tax
$5,736
Difference
−$9
Idaho saves you money
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 Montana to Idaho could save about $9 per year on this profile — roughly 0.01% of gross income.
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