Time commitment
25%Full-time vs part-time, and opportunity cost of the time given.
Splitting equity equally is rarely fair by default. Weigh each founder's time commitment, capital, idea, expertise, responsibilities, and risk to reach a split you can both defend - free and private, nothing leaves your browser.
| Factor | ||
|---|---|---|
Time commitment Full-time vs part-time, and opportunity cost of the time given. Weight: 25 | ||
Capital invested Cash or equivalent each founder puts into the company. Weight: 20 | ||
Idea & IP Who originated the idea and contributes core intellectual property. Weight: 15 | ||
Expertise & skills Domain knowledge and skills critical to building the product. Weight: 15 | ||
Responsibilities Scope of the role and ongoing operational ownership. Weight: 15 | ||
Risk taken Personal and financial risk, e.g. leaving a stable job first. Weight: 10 |
Score each founder 0-10 per factor. Percentages update live and always total 100%.
The calculator is not a verdict. It is a structured way to make hidden assumptions visible before ownership becomes emotional, expensive, and hard to change.
Each founder rates themselves from 0 to 10 across six weighted factors. For each factor, the calculator compares founder scores, applies the factor weight, then normalizes the result so the final percentages always add up to 100%.
Full-time vs part-time, and opportunity cost of the time given.
Cash or equivalent each founder puts into the company.
Who originated the idea and contributes core intellectual property.
Domain knowledge and skills critical to building the product.
Scope of the role and ongoing operational ownership.
Personal and financial risk, e.g. leaving a stable job first.
A split only works if both founders still believe it is fair when the company is under pressure. Use the calculator to start the negotiation, then pressure-test the result against the work each person will actually do.
Equal splits can work, but they should be a deliberate choice after comparing time, risk, capital, expertise, and responsibility.
The split decides the target ownership. Vesting decides how that ownership is earned if someone leaves early.
A defensible split gives both founders a shared logic they can explain to future investors, advisors, and themselves.
Often near 50/50
If both founders join full time, carry similar opportunity cost, and own equally critical work, an equal or near-equal split can be reasonable.
Often weighted toward the earlier full-time founder
Time commitment and personal risk usually deserve extra weight when one founder leaves paid work or carries the company alone for months.
Often adjusted for cash, IP, and future role
Capital, patents, code, or customer access can matter, but ongoing execution should still be weighted so the split stays durable.
Usually role- and risk-based
Multi-founder splits need clearer roles, vesting, and decision rights because small differences become hard to rebalance later.
Each founder should score the inputs privately first. The gap between your answers is often the real conversation.
Discuss where you scored differently: full-time commitment, opportunity cost, capital, expertise, and who owns critical functions.
Once you agree on the split, record the reasoning, vesting schedule, cliff, IP terms, and departure rules in a cofounder agreement.
Before you finalize equity, test your cofounder compatibility across 8 startup-specific dimensions, review the scoring methodology, work through the cofounder questions checklist, then lock the terms in a written cofounder agreement, and use the founder vesting agreement template to discuss how ownership is earned over time.
Cofounders should split equity based on expected long-term contribution, time commitment, capital, idea or IP, expertise, responsibilities, and risk. The result should also include vesting so ownership is earned over time.
A 50/50 split can be fair when founders contribute similar time, risk, expertise, and responsibility. It becomes risky when one founder is part time, contributes much less capital or execution, or expects a very different role.
The original idea can matter, especially when it includes valuable IP or domain insight, but startup value usually comes from execution. The idea should be one factor, not the only factor.
Yes. A fair split defines target ownership, while vesting protects the company if a founder leaves early, stops contributing, or changes commitment level.
This calculator is for informational purposes only and does not constitute legal, financial, or tax advice. Equity decisions should be reviewed with a qualified professional and formalized in a proper agreement.