Co-founder equity split calculator.

Divide equity fairly based on contribution, commitment, capital, and expertise. Six questions per founder, weighted scoring, and vesting recommendations — in a few minutes.

Why this conversation is so important.

The equity split is one of the few startup decisions that compounds — a bad split poisons everything else. A weighted framework beats gut feel every time.

  1. 01
    Equal splits are usually wrong.50/50 is the default but rarely reflects actual contribution. Most failed co-founder relationships started with a lazy equal split.
  2. 02
    Vesting is non-negotiable.Without vesting, a founder leaving in month 3 keeps their full share. 4 years with a 1-year cliff is the standard for a reason.
  3. 03
    Put it in writing.Verbal agreements collapse under pressure. A signed founder agreement with vesting terms saves friendships and companies.
  4. 04
    Get this right early.Splitting equity badly is one of the few mistakes that can't be quietly fixed later. The conversation gets harder, not easier, over time.

How many co-founders?

You'll answer six questions per founder.

What to expect

  1. 01 Answer 6 questions about each founder's contribution.
  2. 02 Get a recommended equity split with the math behind it.
  3. 03 Receive vesting and founder-agreement recommendations.

Common equity-split mistakes.

  1. 01
    Splitting equity too early — before you know who will actually commit.
  2. 02
    50/50 splits by default — rarely matches real contribution.
  3. 03
    No vesting schedule — the single biggest mistake founders make.
  4. 04
    Verbal agreements only — disputes follow, then lawsuits.
  5. 05
    Giving away too much too soon — leaving nothing for employees or investors.

Factors that should matter.

Time commitmentFull-time vs part-time
Capital contributionWho is investing money?
Technical expertiseCan they build the product?
Domain expertiseDo they know the industry?
NetworkCan they open doors?
Original ideaWho came up with it?

This calculator weights each of these — see the full breakdown of what each contribution is actually worth.

More startup tools.

  1. Splitting equity with a technical co-founder

    What each contribution is actually worth, why vesting is non-negotiable, and how to have the conversation.

  2. Vesting calculator

    Calculate vesting schedules and track equity over time with cliff periods.

  3. Cap table calculator

    Model ownership dilution across multiple funding rounds.

  4. All business tools

    The complete collection of free calculators for startups, SaaS, and freelancers.

Got the split sorted? Time to build.

Equity split conversations mean you're past the “what if” stage and into the “let's ship” one. I build startup MVPs and web applications in Next.js and TypeScript — from landing page to full product, typically in 4–8 weeks.

Email me

Built by Taro Schenker — full-stack developer who works with startups and local businesses.