Startup Dilution Calculator (Funding Round, Pre- and Post-Money)
How much of the company you own after a funding round, from your stake, the pre-money valuation, the new investment and any option pool created, with the value of what remains.
Results
The dashed line marks the value you entered.
What this tool does
Pre-money plus the money invested is the post-money valuation, and the investors' share is simply their cheque divided by that post-money number. What founders often miss is the option pool: when investors require a new pool to be created before the round, it is counted inside the pre-money, so only the existing holders pay for it and the effective pre-money is lower than the headline figure. Dilution is not a loss of value by itself — a smaller piece of a larger company can be worth more — which is why the tool also shows what your stake is worth at the post-money valuation.
Formula
post-money = pre-money + investment · investors own investment ÷ post-money · new stake = old stake × (1 − investor share − option pool)
Variables
| Symbol | Meaning | Unit |
|---|---|---|
os | Your ownership before the round | % |
pre | Pre-money valuation | — |
inv | New money invested | — |
pl | New option pool, as % of the company after the round | % |
S2 | Your ownership after the round | % |
PO | Post-money valuation | — |
IP | Share the new investors get | % |
DI | Dilution of your stake | % |
SV | Value of your stake at the post-money valuation | — |
EP | Effective pre-money for existing holders (after the pool) | — |
Worked example
- Your ownership before the round40 %
- Pre-money valuation4,000,000
- New money invested1,000,000
- New option pool, as % of the company after the round5 %
- Your ownership after the round30.00 %
- Post-money valuation5,000,000
- Share the new investors get20.00 %
- Dilution of your stake25.0 %
- Value of your stake at the post-money valuation1,500,000
- Effective pre-money for existing holders (after the pool)3,750,000
Limitations
- This is an informational calculator, not personalised financial advice. Rates, fees, taxes and contract conditions vary between institutions and countries.
- The tool works with whatever currency you use for the inputs; it does not convert between currencies.