Business · Startup equity
Post-money valuation calculator.
Pre-money, post-money, the percent you sell and the price per share, from whichever two you know. Everything runs in your browser.
Raising $2,000,000 at an $8,000,000 pre-money gives a post-money of $10,000,000, so the investors own 20% and existing holders keep 80%. With 10,000,000 shares outstanding the price is $0.80 a share and 2,500,000 new shares are issued.
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The formulas
Pre-money valuation is the value of the company before an investment, calculated on a fully diluted basis, and the post-money valuation is the pre-money plus the cash added (Wikipedia; Cooley GO). The amount external investors put in equals the post-money valuation times the fraction of the company they own after the investment (Wikipedia). So: post-money = pre-money + raise, investor ownership = raise / post-money, and, working backwards, post-money = raise / percent sold.
With the shares outstanding before the round, price per share = pre-money / shares, and the investors receive raise / price new shares.
Worked example
Pre-money $8,000,000, raise $2,000,000: post-money $10,000,000 and investors own 2,000,000 / 10,000,000 = 20%. With 10,000,000 shares, the price is $0.80 and 2,500,000 new shares go to the investors, 12,500,000 in total (investors 2,500,000 / 12,500,000 = 20%). Starting from the percent instead, Y Combinator's SAFE page gives $1M at 15% sold as a post-money of about $6.7M, or $5.7M pre-money; entering 15% and $1,000,000 here gives $6,666,667 post and $5,666,667 pre.
Limits
This is the simple case of one priced round with no option pool change. An option pool created inside the pre-money lowers the effective pre-money (see the option pool shuffle calculator), and SAFEs or notes converting in the round add shares. A valuation is a negotiated number, not a measurement.
Sources, opened 8 October 2026: Wikipedia, Pre-money valuation (pre-money is the valuation before the investment; post-money adds the cash; fully diluted basis); Wikipedia, Post-money valuation (investment equals post-money valuation times the fraction owned); Cooley GO glossary, Pre-Money Valuation; Y Combinator, The SAFE: the standard way startups raise money ($1M at 15% sold, about $6.7M post-money / $5.7M pre).
Frequently asked questions
How do you calculate post-money valuation?
Add the amount raised to the pre-money valuation. $8,000,000 pre-money plus $2,000,000 raised is a $10,000,000 post-money valuation.
How much of the company does an investor get?
The raise divided by the post-money valuation. $2,000,000 into a $10,000,000 post-money is 20%.
How do I find the valuation from the percent I want to sell?
Divide the raise by the percent: post-money = raise / percent sold. Selling 15% for $1,000,000 implies about $6.67M post-money and $5.67M pre-money.
What is a fully diluted share count?
It counts issued shares and the shares that could come from converting preferred stock or exercising options and warrants, and may include the unallocated option pool. Pre-money is calculated on that basis.
Does this include the option pool or SAFEs?
No. It is the simple one-round case. See the option pool shuffle and SAFE calculators for those effects.
Educational only. Not legal, tax or investment advice.
Planning and learning aid only. Real terms depend on the signed documents and your jurisdiction. Tax treatment (409A valuations, 83(b) elections, ISOs and similar) is left to a qualified professional. Amounts are in any one currency; the symbol is only a label.