Compare taxes and see how much you save moving from Washington to Idaho
Washington’s lack of personal income tax is a major advantage for wage earners, saving a $100,000 earner roughly $5,454 per year compared to Idaho’s 5.8% flat tax. The gap grows significantly at higher incomes. Washington does levy a 7% capital gains tax on gains above $262,000, so investors with large portfolios should take note. Washington also has higher sales tax (averaging over 10% in the Seattle metro and 6.5% statewide) versus Idaho’s 6%, and a Business & Occupation (B&O) gross receipts tax on businesses that Idaho does not have. For pure wage earners, Washington is the clear winner; for business owners and retirees drawing capital gains, the picture is more nuanced.
No Income Tax on Wages
No personal income tax; 7% capital gains tax on gains above $262,000
Flat Income Tax
5.8% flat income tax rate on all taxable income
At $100,000 income:
That is $455/month back in your pocket!
| Income | WA Tax | ID Tax | Savings | 10-Year |
|---|---|---|---|---|
| $50,000 | $0 | $2,526 | $2,526 | $25,260 |
| $75,000 | $0 | $3,990 | $3,990 | $39,900 |
| $100,000 | $0 | $5,454 | $5,454 | $54,540 |
| $150,000 | $0 | $8,382 | $8,382 | $83,820 |
| $250,000 | $0 | $14,238 | $14,238 | $142,380 |
| $500,000 | $0 | $28,638 | $28,638 | $286,380 |
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Talk to a CPA About Your State Move →Yes. Since 2023, Washington levies a 7% capital gains tax on long-term capital gains above $262,000 per year. This is separate from income tax and applies to gains from stocks, bonds, and other assets. Gains from real estate sales and retirement accounts are generally exempt. For most wage earners this does not apply, but investors realising large gains should plan accordingly.
The Business & Occupation (B&O) tax is a gross receipts tax on the revenue of businesses operating in Washington. Unlike a corporate income tax, it applies regardless of whether the business is profitable. Rates vary by industry (e.g., 0.471% for retail, 1.5% for services). Idaho has no equivalent tax. For sole proprietors and small business owners, this can be a meaningful consideration when comparing the two states.
Spokane and Boise are both significantly cheaper than Seattle. As of 2026, Boise has experienced rapid population growth that has driven housing prices up sharply, narrowing the cost gap. Spokane generally offers lower housing costs than Boise now, and you’d also avoid Idaho’s 5.8% income tax. The Spokane metro is a popular destination for people who want Washington’s tax advantages at lower cost than the Puget Sound.
Idaho’s 5.8% flat rate is higher than Utah’s 4.55% flat tax and Nevada’s 0%. It is lower than Montana’s top rate of 5.9% and Colorado’s 4.4%. Among Mountain West states, Idaho sits in the mid-range. However, compared to Washington’s 0% on wages, Idaho’s rate represents a significant annual cost for earners at every income level.