Equity Split Calculator
Score each founder on 7 weighted factors to get a fair starting equity split.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this equity split calculator
- Add one row per founder and give them a name.
- Score each founder on the seven weighted factors using a 0-10 scale (10 = maximum contribution).
- Press Calculate split to convert weighted scores into a percentage allocation.
- Iterate openly with your co-founders — re-score, recalculate, and see how each input moves the result.
- Use Copy split to grab the result for your founder agreement draft, or Reset to start over.
About this equity split calculator
Equity splits divide ownership among founders. There is no universal "right" answer, but the most-cited frameworks (Mike Moyer's "Slicing Pie", Y Combinator's "equal split with vesting" guidance) all reduce to a weighted-factor model: rate each founder on the dimensions that matter, weight those dimensions by their importance to the venture, and divide. This tool implements that model with seven factors: original idea (10%), full-time commitment (25%), domain expertise (15%), execution (20%), capital contributed (10%), network & BD (10%), and personal risk (10%). Weights sum to 100%; scores run 0-10.
Worked example. Founder A scores 8 (idea), 10 (commitment), 6 (expertise), 9 (execution), 4 (capital), 7 (network), 8 (risk). Weighted total = 0.10×8 + 0.25×10 + 0.15×6 + 0.20×9 + 0.10×4 + 0.10×7 + 0.10×8 = 0.80 + 2.50 + 0.90 + 1.80 + 0.40 + 0.70 + 0.80 = 7.90. Founder B scores 4, 7, 9, 7, 6, 6, 6 → weighted 6.40. Total = 14.30. Split = 7.90 ÷ 14.30 = 55.2% for A and 44.8% for B. The output is a starting point for negotiation, not a binding decision.
Pair any split with a 4-year vesting schedule (1-year cliff) and a written founder agreement reviewed by counsel.
FAQ
- Why use a weighted-factor model instead of an equal split?
- Equal splits assume equal future contribution, which is rarely true. A weighted-factor split makes the differences explicit so they can be discussed and renegotiated as roles evolve. Equal can still be the right answer — but it should be a chosen answer.
- What does each factor measure?
- Idea = originality of the core concept. Commitment = hours and opportunity cost. Expertise = domain knowledge that de-risks the venture. Execution = day-to-day building and selling. Capital = cash, equipment, paid expenses. Network = customer/investor/hire intros. Risk = giving up a stable job, personal guarantees, signing personally on loans.
- Why is commitment the highest weight?
- Full-time founders out-produce part-time founders 5-10× per month. Most studies of failed startups cite founder departure or part-time attention as a top-three cause. Heavy weighting reflects that risk.
- Should I include vesting?
- Yes — always. The split is the destination; vesting is the path. Standard terms are 4-year vesting with a 1-year cliff. Without vesting, a founder who leaves at month 13 keeps their full stake.
- Can I adjust the weights?
- Not in this tool. The weights are tuned to match the Slicing Pie / YC consensus. If your venture is heavily capital-intensive or research-driven, treat the result as a starting point and discuss explicit adjustments with your co-founders.
- Does this tool save my inputs?
- No. Everything is computed in your browser and discarded on page close. Use Copy to preserve a snapshot.