The washington rsu tax calculator pairs the 22% federal supplemental rate against your real bracket — Washington has no state income tax on RSU vests, so the only state line that may hit later is the 7% WA capital gains tax on sale gains over $270,000. Run your numbers below.
Calculate RSU Withholding
Estimate your RSU tax withholding and net proceeds after vesting.
Try Calculator →Open the Washington RSU tax calculator with these inputs prefilled →
How Washington taxes your RSU vest
Washington has no state income tax, so RSU vesting and ISO exercises are not subject to state income tax. The fair market value of your shares on the vest date hits your W-2 in Box 1 as ordinary wage income at the federal level, but nothing is withheld for Washington at the state line — and nothing is owed at filing time for the vest itself. That's a real advantage for Seattle-area tech employees at Amazon, Microsoft, and elsewhere: the entire state-tax column on every other state's RSU calculator collapses to zero here.
The wrinkle is what happens after you hold and sell. Washington enacted a 7% capital gains tax in 2022, upheld by the WA Supreme Court in 2023, that applies to long-term capital gains exceeding $270,000 per year (per the Washington Department of Revenue). That threshold does not apply at vest — vesting is ordinary income, not a capital gain — but it will apply if you hold the post-vest shares for more than a year and sell them at a large gain.
The two numbers that matter on every vest:
- Federal supplemental withholding rate: 22% on RSU income up to $1M (IRS Publication 15). Above $1M, the rate jumps to 37%.
- Washington supplemental withholding rate: 0% — Washington has no state income tax, so employers withhold nothing for the state on RSU vests.
If your federal marginal bracket is higher than the 22% supplemental rate, your employer is under-withholding the federal portion — and you owe the difference at filing time. There is no parallel state shortfall to worry about in Washington.
Worked examples (Washington, 2025)
These three scenarios use the EquityTax calculator with the inputs shown. The math is identical to what you'll see when you click through to the calculator.
Example 1 — Junior IC, $130K salary, single
Inputs: $130,000 salary, single filer, 100 RSUs vesting at $85 FMV (one vest, March 2025).
Result:
- Total RSU income: $8,500
- Federal withholding: $1,870
- Washington withholding: $0
- Estimated total tax on the vest: $2,690.25
- Shortfall vs default withholding: $170
At a 24% federal bracket and a 0% Washington bracket, the federal supplemental rate of 22% is two points light. The result is a $170 federal shortfall on this vest — small enough to ignore at filing time. Washington's column is flat zero across the board.
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Example 2 — Mid IC, $220K salary, MFJ
Inputs: $220,000 salary, married filing jointly, 400 RSUs vesting at $130 FMV.
Result:
- Total RSU income: $52,000
- Federal withholding: $11,440
- Washington withholding: $0
- Estimated total tax on the vest: $13,068
- Shortfall vs default withholding: $676
At $272,000 of combined household income, the marginal federal bracket is 24% — only two points above the 22% supplemental rate. The shortfall lands at $676 for the vest, well under the safe-harbor thresholds for an underpayment penalty in most cases. The Washington column stays at zero — no state shortfall, no state penalty exposure, no FTB-equivalent filing.
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Example 3 — Senior IC, $350K salary, MFJ
Inputs: $350,000 salary, married filing jointly, 1,500 RSUs vesting at $220 FMV.
Result:
- Total RSU income: $330,000
- Federal withholding: $72,600
- Washington withholding: $0
- Estimated total tax on the vest: $111,690.50
- Shortfall vs default withholding: $31,335.50
This is where the 22% federal supplemental rate falls apart for Washington high earners. A $330,000 vest on top of $350K of base salary pushes the household firmly into the 35% federal bracket. The 22% withholding leaves a $31,335.50 federal gap on the vest. Add the $2,193.49 underpayment penalty and the total owed at filing is $33,528.99. A quarterly federal estimated payment is essentially mandatory at this level. Washington still owes zero at vest — but a future sale of these shares at a gain above $270,000 would trigger the 7% WA capital gains tax.
Run this scenario in the calculator →
Why employer withholding usually isn't enough in Washington
The Washington shortfall story is entirely federal. The 22% federal supplemental rate sits below the 24%, 32%, 35%, and 37% federal brackets that kick in at higher Seattle-area tech incomes. Because Washington has no state income tax, there is no state-side over-withholding to offset the federal under-withholding — every dollar of the federal gap shows up on your return as a balance due.
The fix is straightforward and depends on the size of the gap:
- Adjust your W-4 so your paycheck withholding picks up the difference across the year (IRS W-4 instructions).
- Make a quarterly estimated payment if the shortfall is concentrated around a single vest date — federal estimates go to IRS Form 1040-ES. Washington has no state estimated tax for income.
- Sell-to-cover at vest — if your broker offers it, this can absorb the federal gap automatically.
The 22% federal supplemental rate is a default — not your actual marginal rate. If your total income (salary + RSU) puts you in the 32%, 35%, or 37% bracket, the federal under-withholding can be large — and in Washington there's no state over-withholding to soften it.
How the Washington RSU tax calculator handles your vest
The Washington calculator uses Washington's actual 2025 rules, not a generic state placeholder: zero state income tax on the RSU vest itself, and a note flag for the 7% WA capital gains tax that may apply when you later sell post-vest shares at a long-term gain over $270,000. It separates default employer withholding (22% federal + 0% Washington + FICA) from the incremental tax you'll actually owe based on your full federal bracket — that's how it surfaces the federal shortfall figure that matters at filing time.
Open the calculator with your inputs →
FAQ
Does Washington tax RSU vesting income?
No. Washington has no state income tax, so RSU vesting and ISO exercises are not subject to state income tax. Only the federal supplemental rate of 22% (or 37% above $1M of supplemental wages in a year) and FICA apply at the vest event.
Does the Washington capital gains tax apply to RSUs?
It can apply when you sell post-vest shares, not when they vest. The 7% WA capital gains tax applies to long-term capital gains exceeding $270,000 per year. If you hold RSU shares more than a year after vest and sell at a large gain, the portion of net long-term gain above the $270,000 threshold is subject to the 7% tax.
Why does my Washington RSU vest still leave a shortfall at tax time?
Because the 22% federal supplemental rate is below the marginal federal bracket of most mid-to-senior tech employees in Seattle. The shortfall is entirely on the federal line — Washington has no state component — so the fix is a W-4 adjustment or a federal 1040-ES estimated payment.
Should I make an estimated payment after a big RSU vest in Washington?
If your federal shortfall on a single vest is sizable, you're likely facing an underpayment penalty under IRS Form 2210 unless you cover it via a quarterly federal estimated payment on Form 1040-ES. Washington has no parallel state estimated-tax form for income. Run your scenario in the calculator above to see the exact number.
Sources
- IRS Publication 525, Taxable and Nontaxable Income — RSU treatment, fair-market-value rules.
- IRS Publication 15, Employer's Tax Guide — federal supplemental withholding rate (22% / 37%).
- Washington Department of Revenue — 7% capital gains tax over $270,000 (effective 2022, upheld 2023).
- EquityTax Washington RSU Calculator (internal engine, last verified 2026-05-09).
Tax Disclaimer: This content is for educational purposes only. Always consult with a licensed tax professional or certified public accountant before making financial decisions related to equity compensation, tax planning, or investment strategies.
Estimate only — not financial or tax advice. Consult a qualified CPA before making decisions about exercising stock options, selling equity, or other financial moves.