Co-Founder Equity Calculator

FounderRoleTimeIdea/IPSpecialCapital ($)Suggested (%)
45.38%
54.62%

This is a practical heuristic, not legal advice. Use vesting and a cliff in your final agreement.

About this Co-Founder Equity Calculator

This tool helps founders reach a fair, transparent equity split in minutes. Rate each founder on Role, Time, Idea/IP, Special, and (optional) Capital. Adjust the weights to match your priorities, and the calculator suggests percentages you can copy.

How to use

  • Add each founder’s name.
  • Rate role, time, idea/IP, and special value from 0–10.
  • (Optional) Enter capital contributed; it’s normalized relative to the highest amount.
  • Adjust weights to match your priorities (e.g., early stage: heavier on time/role).

How to fill out the rating

  • Role — How critical and ongoing their responsibilities are (e.g., CEO/CTO/lead engineer, owning roadmap, delivery, hiring). 10 = mission-critical leadership with sustained accountability; 0 = minimal role.
  • Time — Current and near-term commitment (full-time vs. part-time/consulting), including availability and responsiveness. 10 = full-time now with long-term commitment; 0 = negligible time.
  • Idea/IP — Origination of the concept and tangible intellectual property contributed (prior codebase, algorithms, datasets, patents, trademarks). 10 = originated core idea and delivered substantial IP/code; 0 = none.
  • Special — Unique leverage that meaningfully accelerates the business: distribution, sales pipeline, domain expertise, recruiting magnetism, fundraising ability, or key relationships. 10 = outsized, hard-to-replace leverage; 0 = none.

How the split is calculated

  • Weighted scoring: Each factor (role, time, idea, special, capital) is multiplied by its weight and summed.
  • Capital normalization: The highest $ contribution maps to 10; others scale accordingly.
  • Percentages: Each founder’s score ÷ total score → suggested %.
  • Heuristic, not legal advice: Use this as a structured starting point, then finalize with counsel.

Practical tips

  • Vesting + cliff: Standard is 4 years with a 1-year cliff to protect everyone.
  • Late joiners: Re-run the model when someone joins later; issue new grants from an option pool.
  • Cash vs salary: If someone is unpaid, reflect that in time or capital so it’s fair.
  • Decision rights: Equity ≠ governance. Document roles, IP assignment, and decision processes.
  • Keep it simple: Fewer factors beat a 50-question survey. Make trade-offs explicit and move on.

What is an option pool?

  • Equity reserved for future hires (and sometimes advisors), carved from the same 100% cap table.
  • In this calculator, set Configuration → Option pool (%). Founders then share (100% − pool); the table shows the fully-diluted view automatically.
  • Typical size: 5–15% at Seed (often 10–15%), sized to your next 12–18 months of hiring.
  • Example: 60% / 40% → with a 15% pool becomes 51% / 34% (pool 15%).
  • Note: Many investors require the pool pre-money, which dilutes founders, not the investor.

Why founders use this startup equity calculator

  • Clear factors and weights (no black box).
  • Works offline in your browser—we don’t store inputs.
  • Mobile-friendly, instant results, easy export.
  • Built for startup teams who want a quick, fair baseline.

FAQ

  • What’s a “good” split?
    There’s no universal best. Use this co-founder equity calculator to align on priorities (Role, Time, Idea/IP, Capital, Special) and document the decision.
  • How should we set weights?
    Early stage often emphasizes Time and Role; later you may weigh Capital or Special more. Set weights to match your plan.
  • Do we include advisors?
    Advisors typically receive 0.1–1.0% from the option pool with vesting— not from the founder split.
  • We changed our minds—now what?
    Re-run the model with updated inputs and update the written agreement/cap table (keep vesting + cliff).
  • What is vesting (and a cliff)?
    Equity vesting means you earn ownership over time rather than all at once. Standard startup vesting is 4 years with a 1-year cliff: 0% until month 12, then the rest vests monthly. If someone leaves early, unvested shares/options typically return to the option pool or are repurchased by the company.
  • Does this calculator reflect vesting?
    No. It shows target ownership.
  • Does vesting apply to the pool or founders?
    Both. Pool grants (employees/advisors) vest by default. Founders often put their own founder shares on a vesting schedule (reverse vesting). Unvested pool grants return to the option pool; unvested founder shares are usually repurchased/cancelled by the company.
  • Is this legal advice?
    No. This is a practical heuristic—confirm terms with your lawyer.
  • Do you store our data?
    No. All calculations run locally in your browser, nothing is saved.

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