Before you start

An SSN or ITIN
Form W-4 with your employer for federal withholding
Records of foreign income and foreign financial accounts
Records of equity vesting and sales, for the capital gains tax

Step-by-step

1
Complete your W-4 on day one
This sets federal withholding, and in Washington it is the only income-tax withholding form you will file. Getting it wrong is the most common cause of an April surprise, particularly in a two-income household.
Via employerWho: YouFirst week of employment
2
Apply for the WA Cares exemption if you are on a temporary visa
The 0.58% deduction is not income tax but it comes off the same paycheque. Non-immigrant visa holders can apply to the Employment Security Department for a conditional exemption. You apply, and you give your employer the approval letter — the deduction continues until you do.
OnlineWho: YouMonth 1
3
Determine your US tax residency
The substantial presence test counts weighted days over three years to decide whether the US taxes your worldwide income or only US-source income. Certain students and scholars are exempt from counting days for a period. Your visa category does not decide this.
OnlineWho: You
4
Model the capital gains tax before you sell equity
Washington taxes long-term capital gains above a standard deduction at 7% on the first $1 million and 9.9% above that, from 1 January 2026. Real estate and retirement accounts are excluded. If your compensation includes RSUs you intend to sell, this changes the maths — and it did not exist before 2022, so older comparisons omit it entirely.
OnlineWho: You
5
File your federal return by 15 April
There is no Washington income tax return. If you owe capital gains excise tax, that return is separate — and note the due date moved to 1 May 2026 for the 2025 tax year.
OnlineWho: YouBy 15 April annually
6
File an FBAR if foreign accounts exceed $10,000
Aggregate foreign account balances over $10,000 at any point in the year trigger a FinCEN filing, separate from your tax return. A normal current account at home is enough to cross it.
OnlineWho: You

Documents you’ll need

Form W-2 from each employer, issued by 31 January
Form 1099s for freelance, interest and investment income
Equity compensation statements — RSU vesting and sale records, for the capital gains tax
Passport and travel history for the substantial presence day count
Foreign account statements for FBAR reporting

Things most newcomers don’t know

Washington's capital gains tax was retiered from 1 January 2026.

The rate is now 7% on the first $1 million of annual long-term capital gains and 9.9% on the excess — an additional 2.9% on gains above a million. The change first affects the 2025 return and future periods. Any 'no income tax state' comparison written before 2026, and most written before 2022, misses this entirely.

Source: Washington Department of Revenue — new tiered rates for the capital gains tax

The 0.58% WA Cares deduction is exemptible for visa holders, and hardly anyone claims it.

Washington funds a long-term-care benefit from a payroll deduction with no wage cap. Workers on non-immigrant visas can apply for a conditional exemption because they may never be resident long enough to claim. It is your application to make, and the deduction runs until you give your employer the approval letter.

Source: WA Cares Fund — exemptions

A 10.35% sales tax is how a no-income-tax state pays for itself.

Seattle's combined sales tax rate is among the highest in the country, and it is regressive — it falls hardest on people who spend most of what they earn. The headline 'no income tax' is genuinely valuable to a high earner and much less so to someone on a modest salary. Compare the whole picture, not the one number.

Source: Washington Department of Revenue — sales and use tax rates

Your visa does not determine your tax residency.

The substantial presence test — a weighted day count across three years — decides whether the US taxes your worldwide income. Someone on a temporary visa can be a US tax resident; someone on a long visa can fail the test.

Source: IRS — substantial presence test

Common mistakes to avoid

Assuming 'no income tax' means no state tax — Washington has capital gains, sales and payroll levies.
Selling a large equity position without modelling the capital gains excise tax first.
Not applying for the WA Cares exemption while on a non-immigrant visa.
Using a state comparison written before 2022, when the capital gains tax did not exist.
Missing the FBAR because a home-country account did not feel 'foreign'.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.