Idaho vs Washington Taxes
Compare the total tax burden between Idaho (5.3% flat) and Washington (no income tax). Enter your income to see which state saves you more.
| Tax Component | Idaho | Washington |
|---|---|---|
| Federal Tax | $13,170 | $13,170 |
| State Tax | $4,192 | $0 |
| FICA | $7,650 | $7,650 |
| Total Tax | $25,012 | $20,820 |
| Take-Home | $74,988 | $79,180 |
| Effective Rate | 25.01% | 20.82% |
| Annual Difference | $4,192 more | $4,192 less |
The $4,192 difference is primarily because Idaho has a flat 5.3% income tax, while Washington has no state income tax. At your income level, Idaho's marginal rate is 5.3%.
Why the difference
You'd save $4,192/year ($349/month) in Washington vs Idaho.
Tax structure
Idaho has a flat 5.3% state income tax, while Washington has no state income tax.
Effective rate at your income
At $100,000, Washington's effective state rate is 0.0% vs 4.2% in Idaho — a 4.2 percentage point gap.
Tip: With a flat tax rate, your effective state rate is predictable and consistent. Focus tax reduction on pre-tax contributions (401k, HSA) and any state-specific deductions or credits available.
Tip: If you have significant investment income, note that Washington's capital gains tax may apply to gains above the annual threshold (~$278,000 for 2025), and gains over $1 million above that threshold are taxed at 9.9% rather than 7%. For salary-only earners, Washington remains one of the most tax-efficient states.
Idaho Total Tax
$25,01225.01% effective rate
Washington Total Tax
$20,82020.82% effective rate
Annual Savings
$4,192by living in Washington
Idaho vs Washington: Boise's income tax exodus fuels Spokane's zero-tax appeal
Idaho and Washington share a 480-mile border and an increasingly intertwined economy, but their tax philosophies are polar opposites. Washington levies no personal income tax on wages and salaries, while Idaho imposes a 5.3% flat income tax (H.B. 40, 2025, retroactive to 1 January 2025; graduated rates were consolidated in 2023). For a worker earning $150,000, that's a $6,842 annual difference—among the starkest border tax contrasts in the nation.
Washington's capital gains tax took effect for tax year 2022 and survived a legal challenge at the state Supreme Court; the exclusion threshold adjusts for inflation each year and reached $278,000 for 2025, with gains up to $1 million above that threshold taxed at 7% and gains beyond $1 million taxed at 9.9%. This exclusively targets high-income investors and doesn't affect the vast majority of workers. Washington compensates for its lack of income tax with a 6.5% base sales tax (combined rates reaching 10.25% in Seattle) and property taxes averaging 0.81%—both higher than Idaho's equivalents.
The Boise-to-Spokane corridor has become a migration hotspot. Idaho was the fastest-growing state by percentage in the early 2020s, driven by Californians and Washingtonians seeking lower costs. But some Idaho residents are now looking across the border to Washington for tax savings, especially remote workers who can earn Washington-level salaries while potentially living in cheaper eastern Washington communities like Spokane or the Tri-Cities. Coeur d'Alene, just 30 miles from Spokane, has become a test case for this cross-border dynamic.
Key Differences Beyond Income Tax
| Category | Idaho | Washington |
|---|---|---|
| Sales Tax | Base rate 6%, combined up to 9% in some areas; groceries fully exempt | Base rate 6.5%, combined up to 10.25% in Seattle; groceries exempt; no tax on clothing |
| Property Tax | Effective rate ~0.56%; homeowner's exemption reduces assessed value for primary residences | Effective rate ~0.87%; 1% annual levy growth limit; senior/disabled exemptions available |
| Capital Gains Tax | Capital gains taxed as ordinary income at 5.3% flat rate | No income tax on wages, but capital gains tax (effective 2022) taxes gains above an inflation-adjusted threshold—$278,000 for 2025—at 7%, rising to 9.9% on gains over $1M above that threshold |
| Retirement Income | Social Security fully exempt; other retirement income taxed at 5.3% flat rate | No state income tax on any retirement income; no capital gains tax on retirement account withdrawals |
| Business Taxes | Corporate income tax 5.3% flat; no gross receipts tax; various small business incentives | No corporate income tax, but Business & Occupation (B&O) tax of 0.138%-3.3% on gross receipts; can be burdensome for low-margin businesses |
Who Benefits from Moving?
Remote workers earning $120K+ who can work from anywhere
A remote worker earning $150,000 saves $6,842 in state income tax by living in Washington instead of Idaho. Even with Washington's higher property taxes (roughly $1,200 more on a $400,000 home), the net savings are still above $5,600 annually. Spokane offers affordable housing with zero income tax.
Retirees with pension and IRA withdrawals
A retiree drawing $80,000 from pensions and IRAs pays about $3,132 in Idaho income tax. In Washington, it's $0. The property tax difference ($1,200–$1,500 more in WA on a typical home) still leaves Washington ahead by roughly $1,600–$1,900. Eastern Washington retirement communities are an underrated option.
High-income investors with significant capital gains
An investor realizing $500,000 in capital gains pays $26,245 in Idaho income tax versus $15,540 in Washington's capital gains excise tax (7% on gains above the inflation-adjusted threshold, $278,000 for 2025). Idaho taxes all gains above its exempt floor; Washington only taxes the amount exceeding that threshold. Washington saves about $10,705 in this scenario.
Bottom line: At $150,000 in wage income, Washington saves about $6,842 per year over Idaho in state income tax—one of the largest border-state tax gaps in the country, easily justifying a move from Boise or Coeur d'Alene to Spokane for remote workers.
Tax at Different Income Levels
| Income | Idaho Total Tax | Washington Total Tax | Annual Savings |
|---|---|---|---|
| $75,000 | $16,274 | $13,408 | Save $2,867 |
| $100,000 | $25,012 | $20,820 | Save $4,192 |
| $150,000 | $43,051 | $36,209 | Save $6,842 |
| $200,000 | $60,565 | $51,073 | Save $9,492 |
Based on single filer, standard deduction, 2026 tax year. Includes federal income tax, state income tax, and FICA.
Why the difference
You'd save $4,192/year ($349/month) in Washington vs Idaho.
Tax structure
Idaho has a flat 5.3% state income tax, while Washington has no state income tax.
Effective rate at your income
At $100,000, Washington's effective state rate is 0.0% vs 4.2% in Idaho — a 4.2 percentage point gap.
Tip: With a flat tax rate, your effective state rate is predictable and consistent. Focus tax reduction on pre-tax contributions (401k, HSA) and any state-specific deductions or credits available.
Tip: If you have significant investment income, note that Washington's capital gains tax may apply to gains above the annual threshold (~$278,000 for 2025), and gains over $1 million above that threshold are taxed at 9.9% rather than 7%. For salary-only earners, Washington remains one of the most tax-efficient states.
Understanding Each State
Idaho
This state uses a flat income tax rate, meaning the same percentage applies to all taxable income regardless of how much you earn. This simplifies tax planning but means there is no bracket benefit for lower earners. The effective rate is very close to the headline rate after deductions.
Tip: With a flat tax rate, your effective state rate is predictable and consistent. Focus tax reduction on pre-tax contributions (401k, HSA) and any state-specific deductions or credits available.
Washington
Washington has no state income tax but imposes a capital gains excise tax (effective 2022, upheld by the state supreme court in 2023): 7% on long-term gains above an inflation-adjusted threshold ($278,000 for 2025), rising to 9.9% on gains over $1 million above that threshold starting with tax year 2025 (ESSB 5813). The state relies on a relatively high sales tax (6.5% state + local, often totalling 10%+). Washington is a major tech hub (Seattle), attracting high earners who benefit from the lack of income tax.
Tip: If you have significant investment income, note that Washington's capital gains tax may apply to gains above the annual threshold (~$278,000 for 2025), and gains over $1 million above that threshold are taxed at 9.9% rather than 7%. For salary-only earners, Washington remains one of the most tax-efficient states.
Key Comparison Points
Income tax structure: Idaho has a flat income tax (5.3% flat), while Washington has no state income tax.
Beyond income tax: State tax comparisons should also consider property tax rates, sales tax, and cost of living. A state with no income tax may have higher property or sales taxes that offset the savings.
SALT deduction cap: Under OBBBA, the 2026 federal SALT cap is $40,400, phasing out above $505,000 MAGI toward a $10,000 floor. This limits the federal tax benefit of living in a high-tax state, so the gross state tax difference remains close to the net difference for most earners — especially high earners inside the phaseout.
Frequently asked questions
Is it cheaper to live in Idaho or Washington?
Based on income tax alone, Washington has a lower tax burden. At $100K income, you'd save $4,192 annually in Washington compared to Idaho. However, total cost of living also depends on property taxes, sales taxes, and housing costs.
How much would I save moving from Idaho to Washington?
A single filer earning $100,000 would save approximately $4,192 per year in total taxes by living in Washington instead of Idaho. At $150,000 income, the savings change to $6,842 per year.
What is the income tax rate in Idaho?
Idaho has a flat income tax with rates of 5.3% flat.
What is the income tax rate in Washington?
Washington has no state income tax.
Does Washington have income tax?
No, Washington does not levy a state income tax. Residents pay only federal income tax and FICA. However, Washington may have higher property taxes or sales taxes to compensate.