BackStartups

Calculator

Dilution calculator

Enter what you are investing and at what valuation, then let the company raise. This shows what your percentage becomes round by round, what it is worth at exit, and how much of it following on would preserve.

Entry stake
Stake at exit
Total invested
Your proceeds
Multiple
RoundPost-moneyFollowed on?CostYour stake

A model, not advice. It assumes each round sells the stated proportion of the company and that valuations rise by a constant multiple, which real companies do not oblige. It ignores liquidation preferences entirely — see theexit waterfall calculatorfor what those do to your proceeds.

How to read the result

The number most people find surprising is the stake at exit. An entry position of 0.5% becomes something closer to 0.2% after four rounds and a few pool refreshes, and that is the number your proceeds are calculated from — not the one you agreed at entry.

The follow-on rows show the other half of the picture. Maintaining your percentage means investing again at each round, and because valuations rise, each round costs several times the last. That is why most angels follow on once or twice and then stop, and whyreserving capital in advance is the only way to have the option at all.

If the multiple looks disappointing at a valuation you thought was generous, the entry price is usually the cause. Try halving the entry post-money and watch what happens — that single input moves the result more than anything else on the page, which is the argument for taking the valuation cap seriously.

Dilution calculator: common questions

What dilution should I assume per round?
Around 20% is a reasonable planning default for a conventionally raised round, meaning the company sells about a fifth of itself. Larger rounds and heavily competitive markets can run higher; small extension rounds run lower.
Why does the calculator ask for an option pool refresh?
Because pool top-ups are dilution that is easy to forget. Companies typically refresh the employee option pool at or around each significant round, and each refresh reduces every existing holder's percentage by the size of the top-up.
Does this account for liquidation preferences?
No — this calculates your percentage and what that percentage is worth at a given exit value. In a modest exit, the preference stack sitting ahead of ordinary shares can reduce what you actually receive substantially. Use the exit waterfall calculator for that part.