Startup Equity Calculator

Vesting math runs on two numbers: the cliff and the total schedule length. Carta, which tracks vesting terms across its cap-table platform, describes a four-year schedule with a one-year cliff as the most common setup for equity grants, and found at least 95% of the cliffs it sees land on exactly twelve months (Carta, Vesting Explained). That's why both fields default to 48 months and 12 months here, but stay editable.

Below the cliff, the calculator counts zero vested shares no matter how many months you've logged. Past it, vested shares equal your grant multiplied by months worked divided by the total schedule in months, capped at 100%. Multiply that share count by the price per share you entered and you get the current value line.

The second tab skips vesting entirely and runs pure round math. Each row's dilution equals the cash raised divided by the sum of the pre-money valuation and that cash, so a $3 million raise on a $12 million pre-money valuation dilutes existing holders by 20%. Your new ownership after that round is your old percentage multiplied by (1 minus that 20%), and the calculator chains that formula across every row with a raise entered.

Comparable round sizes for your industry are worth pulling before you fill in the pre-money column. Crunchbase's funding database is the common source; our breakdown of what Crunchbase costs covers the paid tiers if the free search comes up short.

None of this checks your actual signed paperwork. A company can promise a grant verbally, put it in a Slack message, or run the whole thing on a handshake, and if the board never approved it in a consent or the stock plan was never filed, cutting that corner leaves you with a number on this page and nothing on a real cap table.

Take a hire granted 40,000 options on a 4-year schedule with a 12-month cliff, who has put in 30 months at the company. Thirty months clears the cliff, so vested shares equal 40,000 x (30 / 48), which comes out to 25,000 shares. At a share price of $8.40, derived from a $42 million valuation divided by 5,000,000 fully diluted shares, those 25,000 shares are worth $210,000 today, even if the company never sells.

Take a founder holding 8% after a priced seed round, watching three more rounds land: a $3 million raise on a $12 million pre-money valuation, an $8 million raise on a $32 million pre-money valuation, and a $15 million raise on a $60 million pre-money valuation.

Every one of those three rounds dilutes at exactly 20%, so the founder's stake runs 8% to 6.4% to 5.12% to 4.096% in three steps. That 20% figure isn't a rounding trick: Carta's Q1 2024 dilution report put median seed dilution at 20.1% and median Series A dilution at 20.5% (Carta, Dilution Is on the Decline), so this example tracks close to the actual median.

Run that same 4.096% against a $500 million exit and the founder's stake is worth $20.48 million before tax, legal fees, or any liquidation preference gets paid out first. Read between the lines of that last clause: preferred stock almost always sits ahead of common in the payout order, so the real check can land lower than the arithmetic above.

Stress-test that $500 million assumption before you accept it outright: run a few growth scenarios through our CAGR calculator first. Our market potential calculator estimates how big the underlying business could plausibly grow, so you can judge if $500 million is realistic.

A funding round's headline percentage and its actual payout are two different things once preferred stock enters the cap table. A 1x non-participating preference just returns the investor's cash first; a 2x participating preference lets that same investor take the lion's share of a modest exit before common stock, including vested options, sees a cent. This calculator has no field for a preference multiple, so it can't tell the two apart.

Investors typically ask for a fresh or expanded option pool to get created before their money comes in. Carta's own guide to pool sizing puts a 10% to 15% pool as the most common range, with 10% the single most frequent choice among the companies it tracks (Carta, Option Pools Guide).

Building that pool before the round adds its own dilution on top of the round's math. Skip that step in your own math and you'll underestimate how much your stake drops.

Nothing here computes tax. Incentive stock options and non-qualified options are taxed on different schedules, at different rates, and the alternative minimum tax can hit an ISO exercise before you've sold a single share. A tax professional who has read your actual grant is the only source for that number.

Options and restricted stock aren't the same instrument. An option needs its strike price paid before the shares are yours; RSUs and restricted stock skip that step and vest straight into ownership. This calculator treats every grant like an option that's already been earned, so a straight RSU grant needs no exercise math at all.

Some grants include acceleration clauses that vest extra shares if the company gets acquired. A single-trigger clause fires on the sale alone; a double-trigger clause also requires you to be let go afterward, and neither shows up in the math above.

An equity promise that never made it into board minutes or a signed option agreement is worth exactly nothing in a dispute. If your company can't produce that paperwork, you're back to square one no matter what this calculator says your shares are worth.

There's no equation for that, and any calculator promising one coefficient for idea, cash, and time is selling you a guess. Research on founding teams by Noam Wasserman found 73% of them split equity within a month of starting the company, and most of those teams locked the split in without revisiting it (Elevate Ventures, summarizing Wasserman's founder research).

This tool only handles the math on shares you already have. Settle the split itself in conversation with your co-founders before any calculator gets involved.

Four years, with a one-year cliff, is what Carta calls the most common setup for equity grants across the companies on its platform. About half of management grants carry a cliff at all, but Carta found the figure rises to close to 70% for employee grants, and when a cliff exists it's set at twelve months at least 95% of the time.

Carta's Q1 2024 dilution report put the median at 20.1% for seed rounds and 20.5% for Series A, both down from roughly 23% to 24% five years earlier. Its 2026 Founder Ownership Report found founding teams retain about 56% of their equity through seed on average and about 36% by the time they close a Series A (Carta, Founder Ownership Report 2026). Treat those figures as a benchmark and still run your own numbers through the second tab.

Carta's guide to pool sizing puts 10% to 15% as the most common range, with 10% the single most frequent choice among the companies it tracks. The right number for your company depends on how many hires you need to reach the next milestone. Match it to that hiring plan, since an oversized pool dilutes everyone before a single option gets granted.

No. Incentive stock options and non-qualified options carry different tax treatments, and exercising ISOs can trigger the alternative minimum tax before you've sold anything. Talk to a tax professional who has read your actual grant, and do it before you exercise.

This calculator assumes vesting accrues evenly by the month once you clear the cliff, which is standard, but some plans vest quarterly or annually after the cliff. Check your actual option agreement for the accrual schedule; on a quarterly plan, round your months-worked input down to the nearest completed quarter before you read the vested-shares line.

Drop this on any page and it renders the calculator above, live, no login or install required. It's free to use; the only ask is leaving the credit link in place.