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Founder Equity Split Calculator

The Founder Equity Split Calculator converts relative contribution scores into a proposed ownership split for up to three founders while reserving a chosen percentage for employees, advisors, or other stakeholders. The scores are weights, not legal measurements, so they can represent an agreed combination of time commitment, prior work, cash, intellectual property, role criticality, and risk. Its purpose is to make a negotiation transparent: changing a score or reserved pool immediately shows the effect on each founder’s percentage. The result should be a discussion starting point supported by vesting, repurchase rights, and written founder agreements.

Inputs

pts
pts
pts
%
Result
—
Founder 1 share of total company equity
Founder 2 equity—
Founder 3 equity—
Total founder equity—

1. Agree on scoring criteria
Decide what each contribution point represents before entering numbers.

2. Enter founder scores
Use relative weights; the scores do not need to total 100.

3. Reserve non-founder equity
Enter the percentage set aside for an option pool, advisors, or other stakeholders.

4. Compare the proposed split
Review each founder’s share of the equity remaining after the reserve.

5. Document the agreement
Translate the negotiated split into formal equity and vesting documents with qualified counsel.

Available founder equity = 100% − Reserved equityFounder equity = Founder score ÷ Total founder scores × Available founder equity

Where:

  • Founder score — relative contribution weight
  • Total founder scores — sum of all entered founder weights
  • Reserved equity — percentage not allocated among founders

Assumptions: All entered scores use the same agreed criteria. The model allocates only percentage ownership and does not set vesting or governance rights.

What the result means

The output is a proportional allocation based entirely on the contribution weights entered.

Equal scores produce equal shares of available founder equity, but equality may not address differences in future commitment or vesting risk.

Given: Scores of 45, 35, and 20; reserved pool = 10%.

Calculation: Total score = 100 and available founder equity = 90%. Founder 1 receives 45/100 × 90% = 40.5%; Founder 2 receives 31.5%; Founder 3 receives 18%.

Result: The proposed cap table allocates 90% to founders and 10% to the reserved pool.

Do founder scores need to add to 100?

No. Only their proportions matter; 45, 35, 20 gives the same split as 4.5, 3.5, 2.

What factors should the scores include?

Teams often discuss prior work, future time commitment, cash, domain expertise, responsibilities, and personal risk. Use criteria everyone understands.

Should the option pool be deducted before splitting founder equity?

This calculator does so because the reserved percentage is removed first. Financing documents may treat pool creation differently.

Can this calculator handle four or more founders?

This page models three founders. For more founders, apply the same proportional formula to all scores in a cap-table spreadsheet.

Why is vesting still important after agreeing on percentages?

Vesting protects the company and remaining founders if someone leaves before completing the expected contribution.