Summary

This dilution calculator models what a new funding round does to your ownership percentage. Enter your current stake, the pre-money valuation, the new investment amount, and any option pool the term sheet creates, then compare pre-money versus post-money pool placement. The math follows standard VC mechanics: post-money equals pre-money plus investment, and the new investor's stake equals investment divided by post-money. Built for founders and operators sanity-checking a term sheet before signing.

Dilution Calculator: Model Your Equity Before You Sign

Run the actual cap table math for post-money valuation, new investor ownership, and your stake after the round.

Calculate your dilution

Dilution calculator

Enter your current ownership, the pre-money valuation, the new investment, and any option pool the round creates. The result updates as you type.

Post-money valuation$0
New investor ownership0.0%
Your ownership after this round0.0%
Your dilution this round-0.0 points

Enter your numbers above to see the result.

Walkthrough

How to run a real round through the calculator

  1. 1

    Start with your current stake

    Use your fully diluted ownership percentage today, not just founder shares. Include any options you already hold and that have vested.

  2. 2

    Enter the round's headline numbers

    Pre-money valuation and new investment usually sit in the first paragraph of the term sheet. Post-money is the two added together, the calculator handles that step for you.

  3. 3

    Set the option pool

    Check the term sheet for the target pool size, commonly 10 to 15 percent of the post-money cap table, and whether it is created pre-money or post-money.

  4. 4

    Read your new number

    The result updates as you type. Compare pre-money versus post-money pool placement to see exactly how many points of ownership each structure costs you.

The math

What the calculator actually computes

Post-money math

Post-money valuation equals pre-money valuation plus new investment. The new investor's stake is investment divided by post-money, with no hidden adjustment.

The option pool shuffle

A fresh option pool created pre-money is a standard VC term. It means existing holders, not the incoming investor, absorb that slice of dilution. Toggle the setting to see the difference.

Your stake, not the cap table average

Aggregate dilution figures hide individual outcomes. This tool applies the round's dilution factor directly to your ownership percentage, not a blended average across the table.

The negotiable part

Why founders get the option pool shuffle wrong

Term sheets rarely spell out who pays for a new option pool. Created pre-money, the pool comes entirely out of existing shareholders before the new investor's stake is even calculated. Created post-money, the incoming investor absorbs part of that cost too. The difference is usually two to five percentage points of your ownership, and it is negotiable, not fixed.

  • Pre-money pool: the standard term, favors the investor
  • Post-money pool: less common, favors existing holders
  • Confirm the pool size and its timing before you sign
Two people shaking hands over a term sheet negotiation with a laptop in the background

Common questions

Is this dilution calculator free to use?
Yes. The calculation runs in your browser. Nothing is sent to a server except an anonymous tool-run signal used for usage stats.
Where does the dilution formula come from?
Standard VC round mechanics: post-money equals pre-money plus new investment, and the new investor's ownership equals investment divided by post-money. This is the same math behind NVCA model financing documents and most priced-round term sheets.
What is the option pool shuffle?
When a term sheet requires a new or expanded option pool to be created before the round closes, pre-money, the cost of that pool falls on existing shareholders, not the new investor. Toggle between pre-money and post-money pool creation above to see how much that shifts your number.
Does this account for multiple funding rounds?
Run it once per round, using your ownership percentage after the prior round as the starting input for the next one. Cumulative dilution compounds round over round.
Does this replace a real cap table tool?
No. Carta, Pulley, and similar platforms track actual share classes, liquidation preferences, and vesting schedules. This calculator estimates dilution from round terms before you get there, useful for a back-of-envelope check ahead of a term sheet negotiation.
What's a typical dilution range per round?
Ranges vary by market and stage, but 10 to 20 percent dilution per round is a commonly cited benchmark in startup finance commentary. Run your own inputs above instead of anchoring on an average that may not fit your round.
Why does my ownership number look lower than expected?
Most first-time founders forget the option pool shuffle. If a term sheet creates a 10 to 15 percent pool pre-money, that pool is subtracted from existing holders before the new investor's stake is even calculated.

Track the funding rounds behind these numbers

aistartupinsights briefs on AI startup funding, hiring, and pricing signals every week. See the deals moving the market.

Get the weekly funding briefing
AI Startup Insights ASI Request access