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Founder equity dilution calculator
Project founder equity ownership through multiple funding rounds — pre-money, post-money, option pool refresh, and dilution per round.
Post-round founder ownership
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- Dilution this round17.4%
- Post-money valuation$38,000,000
- Option pool refresh added7.2%
Founder dilution — the round-by-round math
Every priced funding round dilutes founders by:
- Investor ownership = investment ÷ post-money valuation
- Option pool refresh = additional pool created pre-money to reach target post-money pool
- Combined = founder loses (investor% + pool refresh% × (1 - investor%))
The pre-money pool refresh trick
VCs require a target option pool (10-15% post-round). If the current pool is smaller, the refresh comes out of pre-money — meaning EXISTING shareholders (founders) take the dilution from the pool refresh, not the new investors. This is standard but worth understanding.
Default scenario: $30M pre / $8M invest / 12% pool target → founder dilutes ~21% of their stake. A 65% owner becomes ~51%.
The compounding math
Each round multiplicatively dilutes:
- Seed: 20% dilution
- A: 25% dilution
- B: 18% dilution
- C: 12% dilution
Founders end at: 100% × (1 − 0.20) × (1 − 0.25) × (1 − 0.18) × (1 − 0.12) = ~43% combined founders.
Defenses
- Negotiate option pool out of post-money — rare but possible at hot deals
- Use convertible notes / SAFEs with valuation cap (delays dilution to next round)
- Insist on participating-only-up-to-2x vs full participation (saves founder share at exit)
- Avoid recapping in down rounds — anti-dilution provisions can crush founders
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