Business · Startup equity
Option pool shuffle calculator.
If the new option pool sits in the pre-money, what is your real pre-money valuation? Everything runs in your browser.
Raising $2,000,000 at a $10,000,000 headline pre-money with a pool target of 15% of the post-money share count needs 1,146,341 new pool shares (8,000,000 shares now, 500,000 of them unallocated pool). The price is $1.0933 a share and the effective pre-money is $8,746,667, which is $1,253,333 below the headline.
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What the shuffle is
An option pool is a number of shares reserved for options and other equity incentives, and it typically expands in connection with venture financings (Cooley GO). When new pool shares are created before the investors buy, they count in the fully diluted pre-money share count, so the existing holders bear the dilution and the investors do not. That lowers the effective price paid for the existing company relative to the headline pre-money, which is why it is called a shuffle.
Pre-money and post-money are on a fully diluted basis, and the pre-money plus the amount invested equals post-money (Cooley GO). Write t for the target pool as a fraction of post-round shares, r = raise / (pre + raise) for the investors' share, and O for all existing shares other than the unallocated pool. The post-round total is T = O / (1 - t - r). New pool shares = t x T minus the existing unallocated pool. Price = (pre + raise) / T. Effective pre-money = price x existing shares.
Worked example
8,000,000 shares including a 500,000 unallocated pool (so O = 7,500,000), headline pre-money $10,000,000, raise $2,000,000, target 15%. r = 2,000,000 / 12,000,000 = 16.67%. T = 7,500,000 / (1 - 0.15 - 0.1667) = 10,975,610. The pool must hold 1,646,341 shares, so 1,146,341 are added. Price = 12,000,000 / 10,975,610 = $1.0933. Effective pre-money = 8,000,000 x 1.0933 = $8,746,667, a shuffle cost of $1,253,333. Investors get 1,829,268 shares (16.67%) and non-pool existing holders keep 68.33%.
Limits
The target here is the unallocated pool after the round, and the calculator assumes the whole top-up is created inside the pre-money. Terms vary: investors may specify the pool as a share of post-money or pre-money, include or exclude granted options, or negotiate the size by hiring plan. If your existing pool already meets the target, the result says no top-up is needed and the effective pre-money equals the headline.
Sources, opened 8 October 2026: Cooley GO glossary, Option Pool (a pool of reserved shares for service providers that typically expands with venture financings); Cooley GO glossary, Pre-Money Valuation; Cooley GO glossary, Fully Diluted Shares (counts issued shares and shares that could be claimed through convertible preferred and exercise of options and warrants; may include the unallocated pool depending on context); Wikipedia, Pre-money valuation (calculated on a fully diluted basis).
Frequently asked questions
What is an option pool shuffle?
It is when the new option pool is created before the investment, so its shares count in the pre-money. The existing holders absorb the dilution and the effective pre-money valuation is lower than the headline.
How do you calculate the effective pre-money valuation?
Multiply the price per share by the shares outstanding before the round (not counting the new pool shares). It equals the headline pre-money minus the value of the new pool shares at the round price.
How big should the option pool be?
That depends on your hiring plan and the investor's requirements, and this page cites no published standard. Enter the target from your term sheet.
Does an existing pool count toward the target?
Yes. This calculator counts the unallocated shares you already have toward the post-round target, and only adds the shortfall.
What if the pool is already large enough?
No new shares are needed, the shuffle cost is zero, and the effective pre-money matches the headline.
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.