Cap Table Dilution Calculator
See what a priced round does to your ownership. Enter pre-money, round size, and pre-money option pool top-up; get post-money, investor stake, and your remaining ownership.
The formula
Post-money equals pre-money plus round size. New investor stake equals round size divided by post-money. Total dilution equals investor stake plus option pool. Your new ownership equals prior ownership times (1 minus total dilution).
FAQ
Why is option pool top-up dilutive to founders only?+
Because the top-up sits in the pre-money valuation. New investors dilute-proof themselves; existing shareholders (founders) absorb it.
Can I negotiate the pool?+
Yes. Ask for post-money treatment, smaller size (only what will be granted in 12 months), or shifted post-close.
What if I have multiple share classes?+
This calculator treats ownership as a single fully-diluted number. For preferred-vs-common breakdowns use a full waterfall model.
Does this handle SAFEs?+
No. SAFEs convert at the priced round; run this against the resulting priced round for the true dilution number.
What is a healthy dilution per round?+
Seed: 15–25%. Series A: 20–25%. Series B: 15–20%. Cumulative to Series B is typically 40–55% founder ownership remaining.