RSU Tax Calculator: What You Owe When Shares Vest 2026

The whole vest price is ordinary income

Restricted stock units have no cost basis. When they vest, the full fair market value that day is ordinary income — the same as a cash bonus — and the tax is taken out of it before you see a dollar. On the defaults — shares 100, price $150.00, federal rate 22%, state rate 5% — the ordinary income is $15,000.00, the federal withholding is $3,300.00, the state tax is $750.00, the Social Security is $930.00, the Medicare is $217.50, the total tax is $5,197.50, the net cash is $9,802.50, the net shares retained are 65.35 and the effective rate is 34.65%. That is why the tax looks so big: there is nothing to deduct against it.

At the defaults — shares 100, price $150.00, federal rate 22%, state rate 5% — the ordinary income is $15,000.00, the federal withholding is $3,300.00, the state tax is $750.00, the Social Security is $930.00, the Medicare is $217.50, the total tax is $5,197.50, the net cash is $9,802.50, the net shares retained are 65.35 and the effective rate is 34.65%. Check the identities: ordinary income = shares × FMV per share; federal = income × federal rate; state = income × state rate; Social Security = 6.2% × min(income, $184,500); Medicare = 1.45% × income + 0.9% × max(0, income − $200,000); total tax = federal + state + Social Security + Medicare; net cash = income − total tax; net shares retained = shares − total tax ÷ share price; effective rate = total tax ÷ income × 100. Rounding convention: totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum.

The worked example, line by line

Setup: shares 100, price $150.00, federal rate 22%, state rate 5%.

Line 1 — the ordinary income. 100 × $150.00 = $15,000.00. The whole vest price is ordinary income — there is no cost basis to subtract.

Line 2 — the federal withholding. $15,000.00 × 22% = $3,300.00. This is withholding at the supplemental-wage rate, not your final tax rate — your return reconciles it.

Line 3 — the state tax. $15,000.00 × 5% = $750.00.

Line 4 — the Social Security. 6.2% × $15,000.00 = $930.00 — the income is below the $184,500 wage base, so the full amount is taxed.

Line 5 — the Medicare. 1.45% × $15,000.00 = $217.50 — the income is below $200,000, so there is no additional 0.9% tax.

Line 6 — the total and what you keep. $3,300.00 + $750.00 + $930.00 + $217.50 = $5,197.50. The net cash is $15,000.00 − $5,197.50 = $9,802.50. The net shares retained are 100 − $5,197.50 ÷ $150.00 = 65.35. The effective rate is $5,197.50 ÷ $15,000.00 × 100 = 34.65%.

Reverse: the shares for $10,000 net cash are 102.01 shares (exact 102.0148 shares); at 102.02 shares the income is $15,303.00 and the net is $10,000.51, at 102.01 shares the net is $9,999.53. The price for $20,000 ordinary income is $200.00 — exactly the income. The price for $10,000 total tax is $288.60 (exact 288.6003); at $288.60 the income is $28,860.00 and the total is $9,999.99, at $288.61 the total is $10,000.34. The federal rate for $5,000 federal withholding is 33.33% (exact 33.3333%); at 33.33% the federal withholding is $4,999.50, at 33.34% it is $5,001.00. The shares for $5,000 federal withholding are 151.52 shares (exact 151.5152 shares); at 151.52 shares the income is $22,728.00 and the federal withholding is $5,000.16, at 151.51 shares it is $4,999.83. The price for Social Security to hit the wage-base cap is $1,845.00 (income $184,500.00); at $1,845.00 the Social Security is $11,439.00 and the Medicare is $2,675.25, at $1,844.00 the Social Security is $11,432.80.

Every branch, checked

Shares 50: Income $7,500.00, federal $1,650.00, state $375.00, SS $465.00, Medicare $108.75, total $2,598.75, net $4,901.25, net shares 32.68, effective 34.65%. Half the shares, half the income — every tax line halves, and the net shares are 32.68.

Shares 500: Income $75,000.00, federal $16,500.00, state $3,750.00, SS $4,650.00, Medicare $1,087.50, total $25,987.50, net $49,012.50, net shares 326.75, effective 34.65%. Five times the shares, five times the income — the tax is $25,987.50 and the net is $49,012.50.

Price $50: Income $5,000.00, federal $1,100.00, state $250.00, SS $310.00, Medicare $72.50, total $1,732.50, net $3,267.50, net shares 65.35, effective 34.65%. A third of the price is a third of the income — the tax is $1,732.50 and the net shares are still 65.35.

Price $300: Income $30,000.00, federal $6,600.00, state $1,500.00, SS $1,860.00, Medicare $435.00, total $10,395.00, net $19,605.00, net shares 65.35, effective 34.65%. Twice the price is twice the income — the tax is $10,395.00 and the net is $19,605.00.

Price $1,000: Income $100,000.00, federal $22,000.00, state $5,000.00, SS $6,200.00, Medicare $1,450.00, total $34,650.00, net $65,350.00, net shares 65.35, effective 34.65%. At $1,000 a share the income is $100,000.00 and the tax is $34,650.00 — the net shares are still 65.35.

Price $2,500: Income $250,000.00, federal $55,000.00, state $12,500.00, SS $11,439.00, Medicare $4,075.00, total $83,014.00, net $166,986.00, net shares 66.79, effective 33.21%. At $2,500 a share the income is $250,000.00 — and the Social Security is capped: it is $11,439.00 instead of 6.2% of $250,000, and the Medicare adds $450.00 of additional tax, so the total is $83,014.00 at an effective rate of 33.21%.

Federal rate 37%: Income $15,000.00, federal $5,550.00, state $750.00, SS $930.00, Medicare $217.50, total $7,447.50, net $7,552.50, net shares 50.35, effective 49.65%. The 37% supplemental rate — which applies once supplemental wages pass $1,000,000 in the year — lifts the federal withholding to $5,550.00 and the total to $7,447.50.

State rate 0%: Income $15,000.00, federal $3,300.00, state $0.00, SS $930.00, Medicare $217.50, total $4,447.50, net $10,552.50, net shares 70.35, effective 29.65%. No state income tax cuts the total to $4,447.50 and lifts the net to $10,552.50.

State rate 9.3%: Income $15,000.00, federal $3,300.00, state $1,395.00, SS $930.00, Medicare $217.50, total $5,842.50, net $9,157.50, net shares 61.05, effective 38.95%. A 9.3% state rate — California’s top marginal rate on ordinary income — lifts the state tax to $1,395.00 and the total to $5,842.50.

What the defaults assume

The model assumes the vest is supplemental wages withheld at the rate you enter, that you are single for the additional Medicare threshold of $200,000, and that the state rate you enter is your flat state rate — it does not model state brackets, local taxes, or the net investment income tax, which does not apply to RSU income. It assumes the 2026 Social Security wage base of $184,500. With 0 shares vesting the income is $0.00, all taxes are $0.00, the net is $0.00, the net shares are 0.00 and the effective rate is — (no income, no rate). With a $0 share price the income is $0.00 and all taxes are $0.00. With a 0% federal rate the federal withholding is $0.00, the total is $1,897.50 and the net is $13,102.50. With a $10,000 share price the income is $1,000,000.00, the federal withholding is $220,000.00, the state tax is $50,000.00, the Social Security is $11,439.00, the Medicare is $21,700.00 ($14,500.00 + $7,200.00 additional), the total is $303,139.00, the net is $696,861.00 and the effective rate is 30.31%. Rounding convention: totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum; the reverses are nearest-value solutions, and the exact unrounded figures (102.0148, $200.00, 288.6003, 33.3333, 151.5152, $1,845.00) are stated wherever the rounded figures appear.

Output · formula · meaning

Who uses this

• The employee whose RSUs vest in December: they learn 100 shares at $150 leave $9,802.50 after tax — and they check the $10,000-net reverse (102.01 shares) to see how many shares they need to clear $10,000.
• The $2,500-a-share holder: they learn the Social Security caps at $11,439.00 — and they check the $1,845 reverse to see the exact price where the cap bites.
• The worker with a 37% supplemental rate: they learn the total jumps to $7,447.50 — and they check the 0% state branch ($4,447.50) to see what moving to a no-tax state would save.
• The planner selling to cover: they learn selling to cover leaves 65.35 shares — and they check the 500-share branch (326.75 shares) to see the same ratio at scale.

Accuracy & limitations

The math is first-principles RSU tax: ordinary income = shares × FMV per share; federal = income × federal rate; state = income × state rate; Social Security = 6.2% × min(income, $184,500); Medicare = 1.45% × income + 0.9% × max(0, income − $200,000); total tax = federal + state + Social Security + Medicare; net cash = income − total tax; net shares retained = shares − total tax ÷ share price; effective rate = total tax ÷ income × 100. The 4-decimal exact is shown where the rounding matters: the shares for $10,000 net cash are 102.0148 (shown as 102.01 shares); at 102.02 shares the net is $10,000.51, at 102.01 shares it is $9,999.53. The price for $10,000 total tax is 288.6003 (shown as $288.60); at $288.60 the total is $9,999.99, at $288.61 it is $10,000.34. The federal rate for $5,000 federal withholding is 33.3333% (shown as 33.33%); at 33.33% the federal withholding is $4,999.50, at 33.34% it is $5,001.00. The shares for $5,000 federal withholding are 151.5152 (shown as 151.52 shares); at 151.52 shares the federal withholding is $5,000.16, at 151.51 shares it is $4,999.83. What the model cannot do is your actual return: it does not model state brackets, local taxes, the net investment income tax, or what happens if you hold the shares — selling at vest means no extra gain, holding means capital gain or loss from the vest price. The 22% is withholding, not your final rate — your return reconciles it. For the quarterly payments behind the withholding, see the estimated quarterly tax calculator; for what actually lands in your bank each month, see the take-home pay calculator; for the wage base itself, see the 2026 Social Security wage base page. This is a calculator, not tax advice.