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Equity dilution calculator

Model a funding round and see the new ownership split, price per share and dilution for every owner.

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Equity dilution calculator
Paste a list of owners, one per line as "name;percentage" or "name;number of shares", and this tool works out what a new investment round does to the cap table. It returns the post-money ownership split, the price per share, how many new shares are issued and exactly how many percentage points each existing owner is diluted by. It's built for founders sanity-checking a term sheet, and for anyone comparing two offers before signing one.
The valuation can be entered as pre-money or post-money — the tool converts between them itself. Turn on an option pool to see it carved out of the cap table before the round, which is how most term sheets actually allocate one, and diluting every existing owner along with the new money. Set rounds above one to replay the same investment and valuation figures again on top of the result, useful for seeing how repeated raises on similar terms compound rather than for forecasting different future rounds. A convertible note option applies a discount and a valuation cap instead of a fixed price, converting at whichever gives the note holder more shares.
Owner names and values can use diacritics, emoji or any script, and lines with a missing name, missing value or an unreadable number are simply skipped rather than breaking the whole calculation. Percentage-only cap tables are normalized to 100% and mapped onto a nominal share count so a price per share can be shown; that assumed count cancels out of every ownership percentage, which stays exact regardless. Choose a currency symbol and how many decimal places to show, and switch between a readable breakdown and a plain-text table.
Everything runs in your browser: the cap table, the investment terms and the result never leave your device, which matters for numbers this sensitive. Copy the result, download it as a .txt file, or send it back into the input to run another round on top of it.
FAQ
Do I need exact share counts, or is a percentage enough?
Either works. Give each owner a percentage (like 'Alice;60') and the tool normalizes it to 100% and assumes a round share count so it can show a price per share; the ownership percentages stay exact either way. Give exact share counts instead if you have your real cap table.
What's the difference between pre-money and post-money valuation?
Pre-money is the value of the company before the new investment; post-money is pre-money plus the investment. Set which one you have in the Valuation is option and the tool derives the other.
How does the option pool option work?
A new pool of that size (as a percentage of the post-pool cap table) is created just before the round and dilutes every existing owner, the same way most priced rounds carve one out. Leave it at 0% to skip it.
What does the convertible note option change?
Instead of buying shares at the round's price per share, the investment converts at a discount off that price or at a fixed valuation cap, whichever price is lower — giving the note holder more shares for the same money.
Is my cap table uploaded anywhere?
No. The calculation runs entirely in your browser — the owner list, investment terms and result are never sent to a server.