Independent since 2015
Startup dilution calculator: how much of your company you keep after each round
By Solomon Wiesen, editor. Updated October 2026. Editorial standards | How this site is funded
Model your SAFEs, seed, Series A and Series B rounds and the option pool, and see the founders’ ownership and the value of their stake after every round. The defaults use the median seed and Series A sizes of New York City startups that raised in 2026.
- The median priced seed and Series A rounds on Carta each sold about 20% of the company in 2024.
- Founding teams held a median 56% after the seed and 36% after the Series A (Carta, Founder Ownership Report 2026).
- The option pool and earlier SAFEs usually cost founders more than the round itself.
- A loan dilutes no one: you keep 100% and pay interest instead.
How much of the company the founders keep
The default scenario in the calculator below, against Carta’s medians for real founding teams. A loan of any size leaves ownership where it was.
Startup dilution calculator
Enter what you plan to raise and at what valuations. The calculator converts your SAFEs, tops up the option pool and sells each round, then shows the cap table after every stage and what the founders’ shares are worth at the last valuation.
Startup dilution calculator
Starts with NYC 2026 median seed and Series A sizes, each priced so investors buy 20%. Change any number.
| Round | Amount raised ($) | Pre-money valuation ($) | Option pool after (%) |
|---|---|---|---|
Assumes post-money SAFEs that convert at the first priced round, and an option pool created before the money comes in (the usual term sheet), so the pool dilutes existing holders and not the new investor. Excludes pro rata rights, liquidation preferences, bridges and secondary sales. Nothing you type leaves your browser.
How dilution works, round by round
An investor's share is the money they put in divided by the post-money valuation. Raise $5.5 million on a $22 million pre-money valuation and the post-money is $27.5 million, so the seed investors own 20%. Everyone who held shares before the round now owns 80% of what they had.
Two things make it worse than that headline number.
The option pool shuffle
Most term sheets ask for the employee option pool to be created or enlarged before the new money comes in. The pool then dilutes only the existing holders, which in practice means the founders, while the investor keeps the full 20%. In the calculator's default, a 12% pool plus 20% sold leaves the founders and SAFE holders with 68% between them, not 80%. Carta's data puts the median pool after a seed round at about 12% (Carta), so a request for 20% is worth pushing back on with a hiring plan.
SAFEs and notes stack up quietly
A post-money SAFE converts into the investment divided by its valuation cap. $750,000 on a $10 million cap is 7.5% of the company before the seed even prices, and every additional SAFE adds its own slice. Carta notes that its 20% median for seed rounds does not count the SAFEs and notes that convert into them (Carta).
What NYC startups raised in 2026
Our list of NYC startups that raised money in 2026 tracks 77 rounds worth $12.7 billion. Among the rounds labeled by stage, the median seed was $5.5 million (11 rounds), the median Series A $15 million (11 rounds) and the median Series B $100 million (7 rounds). The list is built from reported rounds, which skew larger than the typical New York raise, so treat these as the upper end. You can download the full CSV.
To see who writes these checks, start with the 24 venture capital firms in New York City, and for AI companies, the NYC AI startups and what they raised.
Dilution versus debt: what the seed money cost
Equity looks free because it has no payment. Its price shows up later. In the default scenario, the seed investors' 11.4% is worth about $20 million at the Series B valuation, for $5.5 million put in. A $5 million SBA 7(a) loan at the October 2026 ceiling of 10% over ten years costs roughly $2.9 million in interest, and the founders keep the company, though they sign a personal guaranty. Startup loans vs. venture capital covers when each one makes sense.
New York founders have more non-dilutive options than most:
- 44 state and city programs, grants and tax credits for New York tech companies.
- The NYC Future Fund, a city loan repaid from revenue.
- For software companies with recurring revenue, SaaS lenders and the SaaS metrics calculator that shows which ones you qualify for.
- The NYC SBA lender finder, for companies with revenue that can carry a payment.
Why the percentage matters at exit
Your percentage at the sale is what you are paid on, after investors' liquidation preferences are paid back. It also interacts with taxes: shares that qualify as qualified small business stock can exclude part or all of the gain, depending on how long you held them. The tax breaks guide has the current holding periods and caps; check your situation with a CPA.
Where to go next
Business valuation calculator
What a company with profits is worth, and what an SBA loan covers.
Frequently asked questions
What is startup dilution?
Dilution is the drop in your ownership percentage when the company issues new shares, to investors, to SAFE holders when they convert, or to an employee option pool. You keep the same number of shares; there are simply more shares in total.
How much dilution per round is normal?
On Carta, the median priced seed and Series A rounds each sold about 20% of the company in 2024, and seed rounds selling 30% or more were under one in ten. Founding teams held a median 56% after the seed and 36% after the Series A, according to Carta's Founder Ownership Report 2026.
How do you calculate dilution?
New investors get the amount they invest divided by the post-money valuation (pre-money plus the new money). Every existing holder is multiplied by one minus that share. If the option pool is topped up before the round, existing holders give up that slice too.
How big should the option pool be?
Carta's data puts the median pool at about 12% after a seed round, and Carta says most companies use only 60% to 70% of the pool before the next raise. A pool sized to your hiring plan for the next two years is easier to defend than a flat 20%.
Do SAFEs dilute founders?
Yes, when they convert. A post-money SAFE gives its holder the investment divided by the valuation cap, so $750,000 on a $10 million cap is 7.5% of the company right before the priced round, and that stake is then diluted by the round like everyone else's.
Does a business loan dilute ownership?
No. An SBA loan, a revenue-based loan or a line of credit is repaid with interest and leaves your ownership unchanged. The trade is a monthly payment and, for SBA loans, a personal guaranty from every owner of 20% or more.
Is this a serial dilution calculator?
No. Serial dilution is a laboratory method for diluting a solution in steps. This page calculates equity dilution: how a startup founder's ownership shrinks across funding rounds.
Want to fund growth without selling equity? Send one short request and a funding partner will contact you about loan options. This is a request for information, not an application, and approval is never guaranteed. We may be paid when you submit a request; see how this site is funded.
General information, not legal, tax or investment advice. Round terms vary widely; have a startup lawyer review any term sheet before you sign.