Calculator
Importance: 0–5 · Contribution: 0–10
| Factor | Importance | ||
|---|---|---|---|
| Full-time commitment from day one | 5 | 5 | |
| Building the product (engineering, design) | 5 | 5 | |
| Sales, fundraising and go-to-market | 5 | 5 | |
| CEO or operational responsibility | 5 | 5 | |
| Domain expertise and network | 5 | 5 | |
| Original idea and insight | 5 | 5 | |
| Work already done before today | 5 | 5 | |
| Cash invested | 5 | 5 |
How to use this calculator
- Set each factor's importance for your startup. A deep-tech company might weight product building at 5; a services-led business might weight sales at 5.
- Rate each founder's expected contribution to each factor over the next few years, not only what they have done so far.
- Read the suggested split as a starting point. If it lands close to equal, consider simply splitting equally.
- Agree vesting (commonly four years with a one-year cliff) and write it all down in a cofounder agreement.
Equal or weighted split?
Founders who start together and commit full time often split equally, because most of the work that creates value is still ahead. A weighted split is fairer when contributions are clearly unequal, such as one founder working part-time, investing significant cash, or joining after the product already exists. Whatever you choose, vesting matters more than the exact percentages: it is what protects the company if someone leaves.
Read more: how to split equity between cofounders, founder vesting schedules, the 83(b) election and what to put in a cofounder agreement.
Frequently asked questions
Should cofounders split equity equally?
Often, yes. Y Combinator almost always recommends "equal (or close to equal) equity splits among co-founders", because "all the work is ahead of you". A weighted split makes sense when contributions are genuinely unequal, for example when one founder is part-time, invests significant cash, or joins after the product already exists.
What vesting schedule should cofounders use?
The common default is four-year vesting with a one-year cliff: 25% of each founder's shares vest after the first year, then the rest vests monthly (1/48 of the total each month) over the next three years. Vesting protects the remaining founders if someone leaves early.
Is the calculator result legally binding?
No. It is a structured starting point for the conversation. Record the agreed split, vesting schedule and IP assignment in a written cofounder agreement, and have a lawyer review it.
How does this equity split calculator work?
You set how important each factor is for your startup (0 to 5) and rate each founder's contribution to it (0 to 10). Each founder's share is their weighted score divided by the total, rounded so the shares add up to exactly 100%.
Still looking for the cofounder to split with?
BiggMate matches founders on skills, commitment and goals, with equity templates built in.