Which number do investors quote?

Increasingly the post-money, because it fixes their percentage regardless of what else goes into the round. Always confirm which basis a term sheet is using: on a £4m raise the difference between a £16m pre and a £16m post is more than three percentage points of ownership.

Where does the option pool fit?

Usually inside the pre-money, which means existing holders fund it. This calculator excludes it deliberately; use the option pool calculator to see the effect.

Free tool

Pre-money / post-money calculator

The core round arithmetic, in both directions: from a pre-money valuation and an investment to the post-money valuation and ownership split, or from an agreed post-money valuation back to the implied pre-money.

DirectionI know the pre-money valuationI know the post-money valuation

Pre-money valuation

Investment amount

Post-money valuation: 20,000,000
Investor ownership: 20.00%
Existing holders after the round: 80.00%

How this is calculated

Post-money valuation = pre-money valuation + investment.
Investor ownership = investment ÷ post-money valuation.
Existing holders keep the remainder: 1 − investor ownership.
Reverse mode: pre-money valuation = post-money valuation − investment.
This ignores option pool changes and converting instruments, which both reduce existing holders' share in practice.

Worked example

£4m invested at a £16m pre-money gives a £20m post-money and 20% for the investor. The same £4m at a £20m post-money is the same deal stated the other way: the pre-money is £16m. £4m at a £20m pre-money is a different deal — 16.7%.

Assumptions

Post-money valuation equals pre-money valuation plus the amount raised, in one currency.
The whole round closes at the same price per share.

Limitations

Does not model converting instruments, pool increases or tranched closes.
Does not model secondary purchases, which move money to sellers rather than into the company.

Prepared by Perseids for general information. This tool runs on the numbers you enter, stores nothing and uses no company data. Results are illustrative and are not legal, tax or investment advice.

Run the same model on your real cap table, with your actual instruments.

Model this on your actual cap table in Perseids

Frequently asked questions

Which number do investors quote?: Increasingly the post-money, because it fixes their percentage regardless of what else goes into the round. Always confirm which basis a term sheet is using: on a £4m raise the difference between a £16m pre and a £16m post is more than three percentage points of ownership.
Where does the option pool fit?: Usually inside the pre-money, which means existing holders fund it. This calculator excludes it deliberately; use the option pool calculator to see the effect.