The equity split your co-founders will still respect in year four.
Nine factors. Weighted. Visible. A number with the math behind it — not a handshake you'll renegotiate at Series A.
Spark plan · Works offline · Print-ready
Most co-founders split 50/50 because the real conversation is awkward.
At month six, one founder is working nights. At month twelve, the other wrote the first check. At month eighteen, nobody can remember why the split made sense. The equity numbers are right there on the cap table; the resentment is not — and nobody has a framework to reopen the conversation.
The default split when founders skip the work. Also the split lawyers warn you against — because it makes every future disagreement a hostage negotiation.
What the Equity Engine weights: idea, time, capital, expertise, network, risk, role, opportunity cost, brand.
The engine is a spreadsheet you can audit. No black box. No "the model said so."
Three moves. The split your co-founder can argue with.
Each founder scores themselves, 0–100, on all nine.
Idea contribution, time committed, capital in, expertise depth, network pull, risk taken, role weight, opportunity cost, brand value. Independent at first. Then you compare.
Decide together what matters most for this company.
A biotech weights risk and expertise. A consumer app weights brand and network. You set the weights once, transparently, and everyone sees how the number moves.
A defensible split with every input visible.
Not 42%/38%/20% because the engine said so. 42%/38%/20% because you can point at each factor, each score, each weight, and defend it. The founder agreement prints from here.
A split that survives the first hard year.
After one sitting:
A number both founders can defend.
When the argument comes — and it will — you point at factors, not feelings.
A print-ready founder agreement.
Split, vesting, cliff, termination — all in one document ready for your lawyer to review.
A baseline you can revisit.
If the shape of contribution changes materially, the engine re-runs. Equity adjustments become math, not drama.
Nobody owns 50% by accident.
The default split is the one you chose with evidence — not the one you defaulted into because the real conversation was hard.