Founder dilution calculator

Set the amount raised, the post-money valuation and any new option pool for each round. Leave a round at 0 to skip it.

Founders' starting ownership (%)

Pre-seed

Amount raised ($)

Post-money valuation ($)

New option pool (% of post)

Seed

Amount raised ($)

Post-money valuation ($)

New option pool (% of post)

Series A

Amount raised ($)

Post-money valuation ($)

New option pool (% of post)

After round	Investors in round	Founders own	Founders' stake worth

How dilution works

Each time you sell new shares, everyone's percentage shrinks. If you raise $2.5M at a $15M post-money valuation, the new investors own 2.5 ÷ 15 = 16.7% and everyone else is scaled down by that amount. Adding a 10% option pool in the same round shrinks existing holders by another 10 points.

A common rule of thumb is that each round sells roughly 15–25% of the company. Founders who keep a meaningful stake after Series A usually avoided over-raising early and kept the option pool sized to a real hiring plan.