Know exactly what you'll keep, and what you'll owe.
Know what you'll actually keep.
Built for the one paycheck nobody explains.Model the taxes on your RSUs, ISOs, NSOs, and shares across an IPO, tender offer, or acquisition — with every step of the math shown. Your numbers stay on your device unless you save, import a statement, or ask the assistant.
- No account required
- Your numbers stay on your device
- Every rule cites its IRS source
The cost of guessing
A liquidity event can be the biggest tax bill of your life. Most people find out in April.
These are the problems that catch equity holders off guard, and how VestMath helps you avoid each one.
A big tax bill you didn't plan for
An IPO or sale can make years of RSUs taxable in one year. A stock sale may have no tax taken out at all. The bill can be five or six figures.
See the bill now, so the cash is set aside before it's due.
Paying tax when the money lands →Too little tax taken out
Companies often take out a flat 22% on RSUs. If you earn a lot, you may owe 35% to 37%.
See how much you're short and exactly what to set aside.
Too little tax withheld: close the gap →Penalties for paying late
The IRS charges a penalty, like interest, from each quarterly due date you miss.
Get the amount to pay each quarter and the date it's due.
Late payment penalties and safe harbors →AMT on shares you can't sell
Exercising ISOs can trigger alternative minimum tax (AMT) with no cash coming in to pay it.
Find out what AMT would cost, and whether waiting or exercising in stages lowers it.
How ISOs are taxed →Stuck in a lockup
After an IPO you usually can't sell for about 180 days. The tax may be due before then, and the share price can drop while you wait.
Plan the sale for the day the lockup ends and see the tax you'll owe then.
IPO lockups: plan your first sale →Bought pre-IPO shares?
Shares bought on the private market don't qualify for the QSBS tax break, and selling within a year of buying means salary-level tax rates.
See your tax on a sale after the IPO, and the date your gain turns long-term.
Buying pre-IPO shares: the tax basics →Free to start. Takes about 5 minutes.
Model every grant type
RSUs (single or double trigger), ISOs, NSOs, early-exercised shares, ESPP, and common stock — each taxed by its own rules, not a blended guess.
See the withholding gap before April does
Your employer withholds a flat 22%. Your real rate is probably higher. We show the shortfall and the exact number to set aside.
Compare exercise timing
Exercise now, at the IPO, at exit, or in stages. See cash needed, AMT, holding periods, and after-tax proceeds side by side.
6,500 RSUs settling at $42
Single filer living in New York City earning $185,000 in salary, so federal, state, and city tax all apply. Double-trigger RSUs settle at the IPO. No shares sold yet.
Estimated after-tax proceeds
Gross value at settlement
Tax caused by your equity
Effective rate on equity
Owed in estimated payments
Avoid a surprise bill
Owing more than you expected?
For commission earners
Big commission checks can throw off your taxes
Commissions and bonuses are often withheld at a flat 22%, well below what many sales earners actually owe. Here's how to spot the gap before April.
Too little tax taken out?
Why 22% withholding on RSUs and zero on stock sales leaves a gap, and how to close it before April.
Penalties for paying late
Underpayment, late-payment and late-filing penalties: what each costs and the safe harbors that avoid them.
Latest guides
Understand the rules before the event
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Traceable methodology
Every calculation cites the Code section or IRS publication it applies. Open "Show the math" on any result and follow each step.
Read the methodologySourced from published tax law
Tax tables are checked against the IRS revenue procedure before they're marked published. Guides cite the Code sections and IRS publications behind every claim.
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The pre-IPO tax checklist
The deadlines, elections, and set-aside math to handle before and after your liquidity event. One email; unsubscribe anytime.