Stage 2 · Plan the raise

Startup Dilution Calculator

Founder ownership after each round, from seed to Series B, including option pool top-ups.

Free, no sign-up. Your numbers stay in your browser.

Please note. Educational only. This is not investment, financial or legal advice. Real rounds depend on the market, your traction and the exact terms you sign. Results are estimates based on what you enter. Full disclaimer · How we build the numbers

What this tool does

Every round sells a slice of the company to new investors and usually tops up the option pool. Both shrink the existing holders' share by the same proportion.

How to use it

Enter the founders' fully diluted ownership today.
Add each round with its raise, pre-money valuation and pool top-up.
Read the founders' ownership after every round.

The maths, in plain view

Investor share = raise ÷ (pre-money + raise)
Founders after = founders before × (1 − investor share − pool top-up)

A worked example

Founders owning 85% who raise a $2M seed at $8M pre (5% pool top-up), an $8M Series A at $32M (4%) and a $25M Series B at $100M (3%) end up with roughly 37%.

Tips

Dilution is not the goal to minimise; the value of your share is. 40% of a bigger company can be worth far more.
Model SAFEs and notes separately: they convert at the first priced round.

Want the full story? Read How post-money SAFEs dilute founders, shown on one cap table.

Questions people ask

How much dilution is normal per round?

Roughly 10-25% per round is common for seed and Series A, before option pool top-ups.

What do founders typically own after Series A?

It varies widely. Founders often hold somewhere around 40-60% combined after a Series A, depending on SAFEs, pool size and how much was raised.

Does the option pool dilute founders?

Yes. When the pool is created or enlarged before a round, the new options dilute existing holders, including founders.

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