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.
How it works
Post-money = pre-money + investment · Investor % = investment ÷ post-money · Price per share = pre-money ÷ pre-money fully diluted shares (existing + pool top-up + SAFE/note conversion shares) · Pool top-up T = (p × post/pre × (E + S) − current pool) ÷ (1 − p × post/pre) · SAFE/note price = lower of cap ÷ capitalization and round price × (1 − discount) · Note amount = principal × (1 + rate × months ÷ 12)
Pre-money is what the company is judged to be worth before the new cash arrives; post-money adds the investment on top, and the investor’s stake is their check divided by the post-money value. Enter whichever you know — the pre-money, the post-money or the stake being offered — and the rest follows. With your cap table entered, the calculator also finds the price per share and the shares issued. Two things in a real round move ownership away from founders without changing the headline numbers. First, the option pool shuffle: term sheets usually ask for an unallocated pool of, say, 10% after the round, created before the investor buys in, so its cost falls on existing holders. Second, SAFEs and convertible notes convert at the lower of the cap price and the discounted round price; their shares are also counted in the pre-money. A post-money SAFE (the current Y Combinator form) prices its cap against a capitalization that includes all SAFEs and notes, so its holder’s share before the new money is fixed at amount ÷ cap. Pre-money SAFEs and notes price the cap against the existing shares only, and notes add accrued interest. The effective pre-money — existing shares × round price — shows what your shares are really valued at once the pool and conversions are paid for.
Worked example
On an $8,000,000 pre-money valuation, a $2,000,000 investment lifts the post-money to $10,000,000 and buys the investor 2M ÷ 10M = 20%. The company has 9,000,000 fully diluted shares (8,000,000 common, 500,000 granted options, 500,000 unallocated) and the term sheet asks for a 10% unallocated pool after the round. The top-up is (10% × 1.25 × 9,000,000 − 500,000) ÷ (1 − 10% × 1.25) = 714,286 shares, so the pre-money share count is 9,714,286 and the price is $8,000,000 ÷ 9,714,286 = $0.8235. The investor receives 2,428,571 shares of 12,142,857. Existing holders keep 74.12% rather than 80%, and founders go from 88.89% to 65.88%. The effective pre-money for existing shares is 9,000,000 × $0.8235 = $7,411,765.
Sources: Y Combinator — Post-money SAFE documents and user guide · Carta — Pre-money SAFEs vs. post-money SAFEs
Frequently asked questions
What is the difference between pre-money and post-money valuation?
Pre-money is the company’s value before the investment; post-money is pre-money plus the new cash. The investor’s ownership is always calculated on the post-money figure, since they own part of the company after their money is in it.
What is the option pool shuffle?
Investors usually require a set unallocated option pool after the round and ask for it to be created before they invest. The new options are then counted in the pre-money share count, which lowers the price per share. Existing holders absorb the dilution and the investor does not. The calculator shows the top-up and the effective pre-money that results.
How does a SAFE convert in a priced round?
The holder gets shares at whichever price is lower: the valuation cap divided by the company’s capitalization, or the round price minus the discount. A post-money SAFE uses a capitalization that includes all SAFEs and notes. Its holder therefore owns amount ÷ cap before the new money, then gets diluted by the round. A pre-money SAFE divides the cap by the existing shares only, so holders of several pre-money SAFEs dilute each other and the founders more than the headline figures suggest.
How is a convertible note different?
A note is debt that converts like a SAFE, but it accrues interest — usually simple interest of 2–8% a year — and the interest converts too. A $500,000 note at 6% for 18 months converts as $545,000.
Why is the investor’s percentage based on post-money?
Because after the round the company is worth the post-money amount, and the investor’s dollars are part of that total. Investment ÷ post-money is the share of the whole they now own. Pool top-ups and SAFE conversions are counted inside the pre-money, so they do not change it.
How do I find the pre-money if I only know the stake?
Choose “Stake offered”: post-money = investment ÷ stake, and pre-money = post-money − investment. $25,000 for 5% implies a $500,000 post-money and a $475,000 pre-money.
Does a higher pre-money always help founders?
A higher pre-money means less dilution for the same raise, which is generally better for founders — but only if the company can grow into the valuation. An inflated pre-money can trigger a painful down round later. Compare offers on the effective pre-money, not the headline number.
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Educational estimate, not financial, tax or investment advice.