Free · Startup calculator

Equity Dilution Calculator

See exactly what your stake becomes after a priced round, and what the investors take.

Free·No signup·Runs in your browser

Calculated

48.00%

Your ownership after the round

Your ownership now 60% · Pre-money valuation $8,000,000

Price
Free
Inputs
3
Account needed
No
Last updated
20 September 2026

Use the equity dilution calculator

This free calculator runs in your browser. Nothing is sent to a server, and no account or email is required. Enter:

  • Your ownership now — Your share of the cap table before this round.
  • Pre-money valuation — Agreed company value before new money arrives.
  • Amount raising — Total new investment in this round.

How it works

  1. 1

    Enter your numbers

    Fill in your ownership now, pre-money valuation and amount raising. Nothing is sent anywhere — the maths runs in your browser.

  2. 2

    Press calculate dilution

    One button. Change any input afterwards and the answer updates as you type.

  3. 3

    Read the result

    You get your ownership after the round, plus post-money valuation, investors take, your stake is worth.

How dilution works

Post-money valuation is pre-money plus the amount raised. The investors own the money they put in as a share of that post-money figure. Raise $2m on an $8m pre-money and post-money is $10m, so investors take 20%.

Everyone already on the cap table is diluted by that same 20%, proportionally. If you owned 60%, you now own 60% x 0.8 = 48%. Your percentage falls, but it falls against a company that just became more valuable — 48% of $10m is more than 60% of $8m.

More on dilution

The option pool shuffle

This calculator excludes the option pool, and that omission is deliberate — the pool is usually where the real negotiation happens.

Investors typically require an employee option pool of 10-15%, created or topped up before the round closes. Because it comes out of the pre-money valuation, existing shareholders absorb all of it. An $8m pre-money with a 10% pool top-up is effectively a $7.2m pre-money for you, and your post-round stake is meaningfully smaller than the headline numbers suggest. Always ask whether a quoted pre-money is before or after the pool.

Dilution across multiple rounds

Dilution compounds. Founders commonly hold 50-60% after seed, 30-40% after Series A, and 15-25% after Series B. Arriving at an exit with 10-20% as a founding team is a normal outcome, not a failure.

The question is never how to avoid dilution — it is whether each round buys enough growth to make the smaller slice worth more. Raising less at a lower valuation is not automatically better if it means you cannot reach the milestones the next round requires.

What this does not model

Convertible notes and SAFEs from earlier rounds convert at this priced round, often at a discount or valuation cap, and they can take a considerably larger share than their face value implies. Liquidation preferences, participation rights and anti-dilution provisions all change what you actually receive at exit regardless of percentages.

For a real round, model the full cap table including converting instruments, and have a lawyer check the terms. Percentages are only part of the picture.

Accuracy and limitations

  • Excludes the option pool. Investors usually require one created pre-money, which dilutes you further than the headline numbers suggest.
  • Does not model SAFEs or convertible notes. Those convert at a priced round, often at a discount or cap, and can take more than their face value implies.
  • Percentages are only part of the outcome. Liquidation preferences and participation rights change what you actually receive at exit.

Frequently asked questions

How do you calculate equity dilution?
Post-money equals pre-money plus the raise. The investor share is the raise divided by post-money. Multiply your existing ownership by (1 minus that share). Owning 60% before a $2m raise at $8m pre-money leaves you with 48%.
What is the difference between pre-money and post-money?
Pre-money is the agreed company value before new investment. Post-money is pre-money plus the amount raised, and it is the figure investor ownership is calculated against.
How does the option pool affect dilution?
The pool is normally created from the pre-money valuation, so existing shareholders absorb all of it. A 10% pool on an $8m pre-money effectively values your shares at $7.2m. Always ask whether a pre-money is quoted before or after the pool.
How much equity do founders typically keep?
Roughly 50-60% after seed, 30-40% after Series A and 15-25% after Series B, varying widely by round size and valuation. Reaching an exit with 10-20% is a normal outcome.
Does this account for SAFEs and convertible notes?
No. Those convert at a priced round, often at a discount or cap, and can take more than their face value suggests. Model the full cap table including converting instruments for a real round.

More ways to run the numbers.

  • SaaS Valuation Calculator A defensible ARR-multiple range driven by growth and margin. Useful before a conversation about price, not instead of one. Open →
  • Startup Runway Calculator How long your cash lasts at the current burn, and the month it runs out — the date every other decision gets scheduled against. Open →
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