Free tool · No signup
Startup Dilution Calculator
See what each funding round does to your ownership — and to the dollar value of your stake. Option pool, YC, seed, Series A and beyond.
Rounds
Final ownership
27.45%
Total dilution
45.1%
Stake value at last round
$16,472,160
Round by round
| Round | Before | After | Stake value |
|---|---|---|---|
| Option pool | 50.00% | 45.00% | $675,000 |
| YC | 45.00% | 41.85% | $747,321 |
| Seed | 41.85% | 34.32% | $4,118,040 |
| Series A | 34.32% | 27.45% | $16,472,160 |
YC Insights Pro
Found the number? Now see how funded founders got theirs.
46 databases and 100+ founder stories on YC applications, valuations, equity splits and first customers — unlimited access for $49/year.
Cancel anytime · 5 free stories a month, no account needed · Secure checkout by Dodo Payments
Next step
YC takes 7% — here is exactly how
$125K for 7% on a post-money SAFE plus $375K uncapped MFN. Read the terms line by line before you model the rest of your rounds.
See the $500K YC deal in detailRelated tools
Free tool
Cap Table Calculator
Turn this into a full multi-holder cap table.
Open toolFree tool
YC SAFE Calculator
Model SAFE conversion at your next priced round.
Open toolFree tool
Cofounder Equity Split Calculator
Set the founder split before any dilution.
Open toolBrowse all free YC tools.
How to use this tool
Step 1
Enter your starting stake
Use the percentage you own today, before any of the rounds below.
Step 2
Adjust the rounds
Set how much of the company each round sells and its post-money valuation.
Step 3
Compare percentage to value
Your percentage always falls; the point is whether your stake's dollar value rises.
Free YC databases
Everything behind this page is in our open databases
Batch lists, rejection case studies, RFS playbooks and launch guides — all free to read, no signup.
Index
List of YC Companies →
Searchable index of YC alumni by batch, from Airbnb (W09) to the newest AI startups.
Database
YC Rejection Database →
Airbnb, Stripe, Reddit — founders who got rejected first, with every source linked.
Playbook
RFS Playbook 2026 →
All 15 YC Request for Startups ideas, each turned into a customer, wedge and 90-day plan.
Browse all free YC databases → · or start on the YCInsight homepage
FAQ
How do you calculate equity dilution?
Your new ownership equals your old ownership multiplied by (1 − new investor percentage). If you own 40% and a round sells 20% of the company, you end at 40% × 0.8 = 32%.
How much dilution is normal per round?
Accelerators take 5–7%, seed rounds 15–25%, Series A 15–25%, and each later round 10–20%. Founders who raise through Series B commonly hold 25–40% combined.
Does the option pool dilute founders?
Almost always yes. Investors typically require the pool to be created before their money goes in, so the pool comes out of the pre-round shareholders — the founders.
Is dilution bad?
Only if the money buys nothing. Owning 20% of a company worth $200M beats 80% of a company worth $2M. What matters is the value of your stake, not the percentage.
Is this dilution calculator free?
Yes. No signup and nothing is stored — all math runs in your browser.
Keep reading
Deep dive
The YC SAFE, Explained →
Post-money SAFE mechanics, cap tables, and what founders actually sign.
Playbook
YC Equity Split for Co-Founders →
Why YC pushes 50/50 splits, when to deviate, and vesting basics.
Deep dive
The $500K YC Deal →
How the standard $125K + $375K SAFE actually works.
Fundraising
Post-Money SAFE Explained →
Cap math, dilution tables, MFN clauses and the four standard forms.
New here? Start on the YCInsight homepage — every YC database, founder story and Q&A in one place. Or jump straight to the free YC databases.