Equity Grant Dilution Calculator
See exactly how much of your startup ownership survives the next funding round. Enter your grant shares, total shares outstanding, and the next-round dilution percentage.
What Is Equity Dilution?
Equity dilution is the reduction in ownership percentage that happens when a company issues new shares. Your share count stays the same, but the total share count grows, so your slice of the pie shrinks. A typical priced venture round dilutes existing shareholders by 15-25%, and multiple rounds compound — a Series A, B, and C together commonly halve founding-team ownership.
How the Calculation Works
Your pre-round ownership is your grant shares divided by total shares outstanding. After a round that sells X% to new investors, your ownership becomes pre-round % × (1 − X%). For example, 1% pre-round with 20% dilution becomes 0.8% post-round. The math is straightforward; the trick is stacking rounds to project all the way to exit.
Option Pool Refreshes
Venture rounds often include an option pool refresh — a top-up to the employee option pool, usually bringing it to 10-15% of post-money shares. The refresh is typically done pre-money, meaning existing shareholders (including you) get diluted more than the headline dilution suggests. Always ask whether the next round assumes a pool refresh and how large it will be.
Why Ownership Percentage Matters
Your dollar payout at exit is ownership percentage × company sale price, minus liquidation preferences paid to investors first. A $100M exit with 0.25% ownership and no preferences pays about $250K. The same $100M exit with $80M of 1x preferences only leaves $20M for common — and your 0.25% pays only $50K. Dilution and preferences together determine your real number.
Frequently Asked Questions
How much dilution should I expect in a typical round?
Priced venture rounds usually dilute existing shareholders by 15-25%. Seed rounds are sometimes smaller (10-20%), Series A-C often 18-25%, and growth rounds can be lower. Option pool refreshes add 3-10% on top, typically taken pre-money from existing shareholders.
Is dilution always bad?
No. A smaller percentage of a much bigger company can be worth more. If a $20M post-money round raises your company value from $50M to $100M, a 20% dilution still leaves you better off in dollar terms as long as the new capital creates real value. Dilution only hurts when rounds are raised at flat or down valuations.
What is a pre-money vs post-money option pool?
A pre-money pool means the refresh is added before the new round, so existing shareholders absorb the dilution. A post-money pool means it is added after and the new investor also gets diluted. Pre-money is standard but worse for employees.
How do liquidation preferences affect my payout?
Preferences pay investors back first before common shareholders (including employees) see anything. A 1x non-participating preference is standard and usually harmless at strong exits. Participating preferences or multiple preferences can dramatically reduce employee payouts even at good exits.
Is this calculator financial advice?
No. This is an informational tool for visualizing percentages. Startup equity valuation depends on liquidation preferences, anti-dilution provisions, secondary transactions, and exit timing. Work with a financial advisor or CPA before major decisions.