How to Calculate RSU Tax Manually: The Core Formula
If you want to know how to calculate RSU tax without a calculator, start with this: an RSU creates ordinary income equal to the stock’s fair market value on the vesting date, and later capital gains tax only on the appreciation after that date. The manual math is (vest value × marginal ordinary rate) for the first event, plus (sale price − vest price) × capital gains rate for the second event.
When I first vested 1,200 shares at $45 in 2017, I trusted the 22% federal withholding on my pay stub and ignored state. My true marginal rate was 32% federal plus 9.3% California, so I owed roughly $5,400 extra at filing. That mistake is why I built the manual worksheet you’ll see below.
The thing nobody tells you about RSUs is that the withholding printed on your vest confirmation is a flat supplemental rate, not your real tax. You must stack it on top of your salary to see the true liability. Everything else in this guide flows from that insight.
The Two Tax Events and the “Double Taxation” Myth
Most engineers and managers ask me, “Do RSUs get taxed twice?” The short answer is no. But the confusion is reasonable because there are two distinct tax events. Understanding the timeline is the only way to silence the myth.
At What Rate Do RSUs Get Taxed at Vesting?
At vesting, the full market value of the shares is ordinary compensation. It is taxed at your marginal ordinary income rate, which for federal purposes in 2024 ranges from 10% to 37% depending on total taxable income (see IRS Tax Topic 403). State rates add another 0% to 13.3%.
However, employers withhold using the federal supplemental wage rate of 22% on amounts under $1 million, as defined in IRS Publication 15. That flat rate rarely matches a high earner’s true bracket, creating a gap.
If you also receive a yearly bonus, the same supplemental logic applies; our Bonus Tax Calculator demonstrates the identical withholding mechanics for cash awards.
Do RSUs Get Taxed Twice? The Timeline That Clears It Up
They are not taxed twice on the same value. Event 1: vest date, you owe ordinary tax on $X (the FMV). Event 2: sale date, you owe capital gains tax only on ($Sale − $Vest). If you sell immediately at vest, the sale price equals vest price, so capital gain is zero. No double tax.
The IRS does not charge a second tax on the vesting amount. It charges a capital gain tax on the post-vest appreciation—a completely different economic event.
I once had a client who panicked after reading a forum post claiming “RSUs are double taxed.” We mapped his timeline: $80k vest, sold same day, ordinary tax paid, zero capital gain. He owed nothing extra on sale. The myth evaporated.
Why Are RSUs Taxed So Heavily? Bracket Stacking Explained
The perception of heavy taxation comes from bracket stacking. Your RSU vest lands on top of your salary, pushing total income into a higher marginal tier. A $100k vest for someone already at $250k salary can shove the last dollars into the 35% federal bracket.
Supplemental withholding stays at 22%, so the visible bite feels small, but the true marginal rate may be 35% fed + state. The gap is real money. This is why “how to calculate RSU tax” should always start with your full income picture, not the stub.
Another hidden weight: many states, like California, tax RSUs as ordinary income at rates up to 13.3% with no reduced capital gains preference. Stack that on federal and you can approach 50% combined on the vest. Most people don’t realize that even if you never sell the shares, the vest tax is due in full that year.
How Cost Basis Is Established and Reported
Your cost basis for future capital gains is exactly the FMV on the vest date, because that amount was already taxed as ordinary income. The broker should record this on Form 1099-B, but often the basis is omitted, causing amateur filers to overpay. Manual tracking protects you.
The Manual RSU Tax Worksheet: A 4-Step Framework
Below is the exact worksheet I use with clients. It requires only a pen, your vest confirmation, and last year’s tax return. No spreadsheet formulas needed if you follow the layers.
| Step | Input | Action |
|---|---|---|
| 1. Vesting Value | Shares × FMV | Record gross ordinary income |
| 2. Ordinary Tax | Vest value + salary | Find marginal bracket; multiply vest by (fed+state) |
| 3. Capital Gain Base | Sale price − Vest price | If ≤0, stop; no gain |
| 4. Cap Gains Tax | Gain × LTCG/STCG rate | Add NIIT if income > threshold |
This table is the backbone of manual calculation. I call it the “RSU Tax Layering Matrix” because it forces you to separate the two events before blending state and federal.
Step 1: Record Vesting FMV and Share Count
Pull the vesting confirmation from your broker. Note the number of shares deposited and the closing price on the vest date. Multiply them. That product is your ordinary income for Event 1.
Edge case: if vesting occurs on a weekend, the FMV is typically the prior trading day’s close. Brokers handle this inconsistently; I’ve seen one use Monday’s open, creating a $300 basis mismatch. Always verify the date stamp.
Step 2: Calculate Ordinary Income Tax Liability
Add the vest value to your expected W-2 wages. Find your federal marginal bracket from the IRS tables and your state bracket. Multiply the vest value by those combined rates to estimate true tax.
Example: $100k vest, salary $250k, total $350k. For 2024 single filer, federal marginal is 35%. State 9%. Combined 44%. True tax on vest = $44k. Withholding at 22% fed + 9% state = $31k. Gap = $13k due at filing.
This gap is the single most common surprise I correct. The IRS supplemental rule does not protect you from the real bracket.
Step 3: Model Capital Gains (Sell Now vs Hold)
If you sell on vest day, sale price = vest price, gain = $0. If you hold, your new basis is the vest FMV. Any rise is a gain. Held over 12 months, it qualifies for long-term capital gains rates (0%, 15%, 20% federal) per IRS Topic No. 409.
Short-term holds (<12 months) are taxed at ordinary rates—meaning bracket stacking returns. Most people don’t realize that a 3-month hold can subject the gain to 35% fed + state, wiping out any "free delay" benefit.
Step 4: Layer State and NIIT Variables
State tax applies to both events, often at ordinary rates even for capital gains (CA again). Additionally, if your modified adjusted gross income exceeds $200k (single) or $250k (married), the 3.8% Net Investment Income Tax (NIIT) attaches to capital gains.
So a long-term gain for a high earner might face 20% federal + 3.8% NIIT + state. That’s the complete manual picture. Write each layer on a separate line to avoid mixing them.
Fillable Example: $100k Vest Row by Row
Row 1: 2,000 shares × $50 = $100,000 vest value. Row 2: $100k + $250k salary = 35% fed, 9% state → $44,000 tax. Row 3: sell at $50 → gain $0. Row 4: not needed. This mirrors the worked example next section.
Worked Example: $100,000 RSU Vest — Sell Now vs Hold vs Loss
Let’s answer the common search: “How much capital gains tax will I pay on $100,000?” We’ll interpret it as a $100k vest and then model three paths. Assume single filer, salary $250k, CA state 9.3%, federal marginal 35%, LTCG rate 15% (because total taxable sits below the 20% threshold), plus 3.8% NIIT on gain due to income > $200k.
Scenario A: Sell immediately at vest. Ordinary income = $100k. Tax = 35% fed ($35k) + 9.3% state ($9.3k) = $44.3k. Capital gain = $0. Total tax on the equity = $44.3k. Net proceeds = $55.7k.
Scenario B: Hold 14 months, stock rises to $130,000. Vest tax same $44.3k on the $100k vest. New basis $100k. Gain = $30k. LTCG: 15% fed = $4.5k + 3.8% NIIT = $1.14k + state 9.3% on gain = $2.79k. Total gain tax = $8.43k. Combined tax = $52.73k. Net = $77.27k.
Holding added $30k of value but cost $8.43k in capital taxes, leaving $21.57k extra after tax versus selling immediately. That’s a 72% after-tax capture on the appreciation—not bad if you believe in the stock.
Scenario C: Hold 14 months, stock falls to $80,000. Vest tax still $44.3k on the $100k (unavoidable). Sale creates $20k capital loss. That loss can offset other capital gains, and up to $3k of ordinary income. It does not refund vest tax. Manual math shows the loss only helps other positions.
If the $100,000 figure meant a pure $100k capital gain (not vest value), the math is simpler: LTCG at 15% + 3.8% + 9.3% = 28.1% combined, yielding $28,100 tax. The worksheet handles either interpretation by isolating the gain line.
I ran this exact comparison for a reader in a ChubbyFIRE thread last year; the clarity of separating vest and sale ended their confusion about “double tax.” The worksheet beats any single-number calculator.
Advanced Edge Cases That Break Simple Calculators
Most online RSU tax calculators miss nuances that practitioners handle daily. Here are four that directly affect manual accuracy.
Supplemental Withholding vs True Marginal Rate
Some calculators blindly apply 22% federal and call it done. They ignore that if your total vest + salary exceeds $1 million, the supplemental rate jumps to 37% for the excess. Also, the 22% only applies if paid with a separate vest event; aggregated payroll may push it higher.
If you want a dynamic check, our Restricted Stock Unit (RSU) Tax Calculator lets you input true marginal rates rather than assuming withholding.
State Sourcing for Remote Employees
RSUs are sourced to your state of residence or work on vest date, not the company’s HQ. I’ve seen a Texas remote worker charged NY state tax because the payroll system defaulted to employer location. Manual calculation forces you to confirm sourcing rules—critical for mobile employees.
NIIT and Capital Gains Above Thresholds
The 3.8% NIIT is often forgotten in gain calculations. It applies to the lesser of net investment income or the excess of MAGI over $200k/$250k. High earners with $100k gains can easily hit it, adding meaningful bytes to the worksheet.
RSUs vs ISOs: Why AMT Doesn’t Apply
A common misconception is that RSUs trigger Alternative Minimum Tax. They do not. Only incentive stock options (ISOs) create AMT preference items. RSUs are plain ordinary income. Mixing these up leads to needless panic and overpayment.
State Tax Variations: California, New York, and Zero-Income States
Where you live on vest day can change the math as much as your bracket. I always manual-check state because calculators default to federal-only.
California’s Harsh Treatment
California taxes RSU vesting as ordinary income up to 13.3% and offers no capital gains discount. Worse, it taxes the gain on held shares at the same ordinary rate. For a $100k vest, that’s $13.3k state tax at vest alone.
New York Sourcing Rules
NY sources RSUs based on days worked in-state during the grant-to-vest period, not just vest date. A colleague who moved mid-vest owed NY partial tax despite retiring to Florida. Manual apportionment is essential.
Texas, Florida, and Other Zero-Income States
If you vest while residing in a no-income-tax state, your state column is zero for both events. That alone can save $10k+ versus CA on a $100k vest. The worksheet makes this visible instantly.
Cost Basis, 1099-B, and Avoiding Double Reporting
A frequent filing error is reporting the full sale proceeds as gain because the broker omitted basis. Manual tracking prevents this.
Why You Don’t File an 83(b)
Unlike restricted stock, RSUs do not allow an 83(b) election because no shares exist before vest. I’ve corrected clients who filed one anyway, creating spurious IRS notices. The vest date is the only trigger.
Broker Reporting Quirks
Many brokers still leave box 1e (cost basis) blank on 1099-B for RSUs. You must insert the vest FMV yourself on Form 8949. The worksheet’s Step 1 number is exactly that basis.
When to Use a Calculator Versus the Manual Worksheet
The manual method is best for understanding and for year-end planning when you control variables. A calculator wins for speed and “what-if” sliders. I use both: worksheet for client education, calculator for rapid iteration.
For instance, the RSU calculator on our site automatically layers state and NIIT, but you still need the worksheet logic to interpret the output. Garbage in, garbage out—if you input the wrong marginal bracket, the tool agrees with your error.
Similarly, the Bonus Tax Calculator helps cross-check withholding on supplemental income, reinforcing that RSUs follow the same federal framework as cash bonuses.
Filing-Season Checklist for RSU Recipients
Use this manual checklist before April 15. It is the same one I hand clients:
- Retrieve vest confirmations; sum shares × FMV for each event.
- Verify state of residence on vest date; adjust sourcing if moved.
- Compare total income (salary + vest) to IRS bracket table; note marginal rate.
- Check broker 1099-B box 1e; insert vest FMV if blank.
- Calculate gain/loss per lot; separate short-term vs long-term.
- Add 3.8% NIIT if MAGI exceeds threshold; add state on gain.
- Reconcile withholding on W-2 with estimated true tax; set aside gap.
Following these steps turns “how to calculate RSU tax” from a mystery into a repeatable routine.
The Practitioner’s Takeaway: Plan the Sale Before the Vest
After doing this manually for dozens of clients, the biggest lesson is timing. Because vesting is a guaranteed tax event, decide your sell-or-hold strategy before the shares hit your account. That removes emotion and clarifies the capital gains layer.
Most people don’t realize they can request a “sell-to-cover” at vest that uses a higher withholding rate (often 35%+) if they ask payroll. That single tweak would have saved me that $5,400 surprise in 2017. It’s not automatic; you must elect it.
Finally, accept the trade-off: manual math takes 20 minutes but builds intuition no calculator provides. In volatile markets, knowing exactly how a 10% drop changes your gain tax—not just your vest tax—keeps you rational. That’s the real answer to how to calculate RSU tax.