Startup Equity Dilution Calculator

Track dilution across rounds and pool adjustments. Compare cap tables, prices, and outcomes for teams. Protect long term ownership and negotiate better terms today.

Inputs

Enter current shares, then model up to three priced rounds with optional pool refresh rules.

Used only for display and exports.
Issued to founders before fundraising.
Already granted options or shares.
Remaining pool before the first round.
A simple ownership value estimate.
Used only when the checkbox is enabled.

Funding rounds (enable up to 3)

Share price is based on fully diluted pre-round shares, including any existing unallocated pool.

Round 1
Common in term sheets; may increase dilution.
Adds shares before investor shares are issued.
Round 2
Common in term sheets; may increase dilution.
Adds shares before investor shares are issued.
Round 3
Common in term sheets; may increase dilution.
Adds shares before investor shares are issued.

Example data table

A sample scenario to show typical inputs and outputs.

Scenario Starting shares Seed pre-money Seed investment Target pool % Founder final %
Sample 9,000,000 $8,000,000 $2,000,000 15% ≈ 63–67%
More dilution 6,000,000 $6,000,000 $3,000,000 20% ≈ 50–58%
Lower dilution 12,000,000 $18,000,000 $3,000,000 10% ≈ 70–78%
Values are illustrative; your results depend on your exact share counts and terms.

Formula used

  • Fully diluted pre-round shares: Spre = founder + granted employee + unallocated pool + prior investors
  • Share price: price = pre-money valuation / Spre
  • New investor shares: I = investment / price
  • Post-money valuation: post-money = pre-money + investment
  • Ownership percentage: ownership = holder shares / total post-round shares
  • Pool target after round (optional):
    If target pool fraction is t, then additional pool shares x satisfy: (pool + x) / (Spre + I + x) = t, so x = ( t(Spre + I) − pool ) / (1 − t), floored at zero.
  • Dilution: dilution = 1 − (final % / starting %)

How to use this calculator

  1. Enter current founder, granted employee, and unallocated pool shares.
  2. Enable Round 1 and fill in pre-money and investment amounts.
  3. Choose whether the pool stays the same, is refreshed, or is expanded.
  4. Enable additional rounds if you want to model later financing.
  5. Optionally add an exit valuation to estimate ownership value.
  6. Press Calculate to see dilution, cap tables, and details above.

FAQs

1) What does dilution mean for employees?

Dilution means your ownership percentage drops when new shares are issued. Your share count stays the same, but the total share count increases.

2) Why does a pool refresh increase dilution?

A pool refresh adds new option shares before or around a financing. Those new shares reduce everyone else’s percentage, unless you receive additional grants.

3) Is the unallocated pool treated as owned?

It is not owned by any person yet, but it is included in fully diluted shares. That’s why it affects pricing and dilution in many term sheet models.

4) What is a post-money pool target?

It means investors want the remaining pool to equal a chosen percent after the round closes. This typically pushes pool expansion onto existing holders.

5) Does the calculator model liquidation preferences?

No. It models ownership percentages and simple value at a headline exit valuation. Preferences, participation, and waterfalls can change payouts significantly.

6) How should I enter restricted stock or RSUs?

If they are already issued, include them in the granted employee shares. If they are planned but not issued, consider placing them into the unallocated pool.

7) Why is share price based on pre-money and shares?

In a priced round, price per share is often derived by dividing the negotiated pre-money valuation by the fully diluted share count before the round.

8) Can I model multiple investors in one round?

Yes, combine the investments for that round. If terms differ by investor, model separate rounds or use the round notes to track assumptions.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.