How to Split Founder Equity Fairly

Three founders, an equal split, no vesting, agreed over a weekend because the alternative conversation was uncomfortable.

Fourteen months later one has left for a salaried job and holds a third of the company. Every investor who looks at the cap table asks the same question, and there is no good answer.

Vesting matters more than the split

The percentages are what founders argue about. Vesting is what determines whether the split survives contact with reality.

Vesting means equity is earned over time rather than granted outright. The standard structure is four years with a one-year cliff: nothing vests for twelve months, then a quarter vests at once, then monthly thereafter.

The cliff is the important part. A founder who leaves in month eight leaves with nothing, which is the correct outcome — they contributed eight months and the company has years ahead of it.

Without vesting, an early departure leaves a large dead-weight holding: equity owned by someone contributing nothing, which cannot be reallocated to whoever does the work instead, and which every future investor will require cleaning up before investing.

Vesting protects everyone, including the person who leaves. It converts an uncomfortable negotiation at departure into a term everyone agreed to in advance.

What the split should reflect

Contribution across several dimensions, weighted by how much each matters to this particular company:

Capital — money put in, valued as money rather than as effort.

Time committed — full time from the start is a different contribution from evenings and weekends, and the difference is large.

Expertise and prior work — a founder bringing existing IP, a customer base or a domain reputation is contributing something the others cannot replicate.

Risk taken — leaving a salaried job is a real cost that the founder still employed elsewhere is not bearing.

Running the model under two weightings and comparing is more useful than settling on one. The spread between capital-heavy and time-heavy is the conversation the founders need to have, and seeing it as numbers makes it easier to have calmly.

Equal is a decision, not a default

An equal split among founders contributing equally is right and simple.

An equal split among founders contributing very differently stores up resentment, and resentment between founders is among the most common ways early companies fail. The founder doing four days a week beside the one doing five hours notices, and notices for years.

What makes equal splits attractive is that they avoid a difficult conversation at the point where everyone is enthusiastic. That conversation does not go away; it is deferred to a point where it is much harder.

What the model cannot cover

The output is a starting point for a discussion. The agreement that follows needs a lawyer, and it needs to cover more than percentages:

Vesting terms including the cliff and what happens on departure.

Good leaver and bad leaver provisions — whether someone dismissed for cause keeps vested equity.

IP assignment, ensuring work done belongs to the company rather than the individual.

Decision rights, particularly what needs unanimity.

What happens if someone stops contributing without formally leaving, which is the messiest case and the one most often unaddressed.

That is the cheapest legal work a company ever buys, and skipping it is the most expensive saving founders make.

Common mistakes to avoid

• No vesting, or vesting with no cliff.
• An equal split chosen to avoid the conversation rather than because it fits.
• Valuing a promise of future work as though it were already delivered.
• Leaving IP assignment out of the agreement.
• Agreeing terms verbally and documenting them later, which frequently means never.

How to do it with Partnership Equity Splitter

The Partnership Equity Splitter models the split and the vesting.

1. List each founder’s contribution across capital, time, expertise and risk.
2. Run more than one weighting and compare — the spread is the discussion.
3. Model the four-year vest with a one-year cliff.
4. Take the outcome to a lawyer to draft, including leaver provisions and IP assignment.

Other business calculators are in the tools directory.

Frequently asked questions

Should equity be split equally?

Sometimes, and it should be a decision rather than a default. An equal split among founders contributing very differently stores up resentment, which is a common cause of early-stage failure.

Why does vesting matter more than the split?

Because a founder leaving early without vesting keeps a large holding while contributing nothing. That dead weight damages every future funding round, and vesting prevents it for everyone including the leaver.

Is this a legal document?

No. It models a split. Vesting, leaver provisions, IP assignment and decision rights all need a lawyer, and that is the cheapest legal work a company ever buys.

Final thought

Agree the vesting before the percentages. The split is a guess about contributions that have not happened yet; vesting is what makes the guess correctable.

Try the free Partnership Equity Splitter