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Cap Table Ownership Calculator

Turn a share count into an ownership percentage — both basic and fully diluted once the option pool is counted.

Your shares

Total shares issued

Option pool (unissued)

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How it works

Basic % = your shares ÷ total issued shares × 100 · Fully diluted % = your shares ÷ (total issued + option pool) × 100

Basic ownership divides your shares by the shares actually issued today. Fully diluted ownership also counts shares reserved but not yet issued — the unallocated option pool, warrants and convertibles — because those will eventually become real shares and shrink your slice. Investors and acquirers almost always negotiate on the fully diluted number, so it is the one that matters at exit.

Worked example

You hold 1,000,000 of 8,000,000 issued shares — a 12.5% basic stake. With a 1,000,000-share option pool still unissued, the fully diluted base is 9,000,000, so your fully diluted ownership is 1M ÷ 9M = 11.11%.

Frequently asked questions

What is the difference between basic and fully diluted ownership?

Basic uses only shares issued today. Fully diluted also includes the option pool, warrants and convertible securities that will become shares later. Fully diluted is always lower and is the figure used in fundraising and acquisition talks.

Should the option pool be included?

For any forward-looking decision, yes. Unallocated pool shares will be granted to employees and dilute existing holders, so the fully diluted percentage reflects your true long-run ownership.

Why does my percentage keep changing?

Each new share issuance — a funding round, an option grant, a convertible converting — increases the total share count, so a fixed number of shares becomes a smaller percentage over time.

Related calculators

Equity Dilution Calculator

See how a new funding round dilutes your ownership — your stake before and after, the investor’s slice, and the dilution factor.

Option Pool Impact Calculator

See who pays for a new option pool: how a pre-money pool carve-out splits ownership between founders and the incoming investor.

Employee Equity Value Calculator

Value a stock option grant as it vests: vested shares, the gain over your strike price, and what the whole grant is worth.

Pre & Post-Money Valuation Calculator

Work out post-money valuation, investor ownership and price per share from the pre-money, post-money or the stake offered — with SAFE and convertible note conversion (cap, discount, interest), the option pool shuffle and a cap table before and after the round.

Educational estimate, not financial, tax or investment advice.