How Much Equity Should I Give My Cofounder?

This startup founder equity calculator helps you answer the question that haunts most early-stage teams…

100% of equity in nothing is still nothing. But equity sets the tone for how founders show up — today and five years from now.

This isn't just about percentages. It's about ownership, trust, and what happens when the shine wears off. A few percent might not matter now — but they will when things get hard.

This page is built to help you:

Think before you split
Avoid the scar tissue of misaligned equity
Use our calculator as a mirror, not a scoreboard

Still wondering how much equity you should give your cofounder? This startup equity calculator doesn't give you the answer — it helps you ask the questions most founders avoid. It's designed to surface misaligned assumptions before they cost you your company.

What This Cofounder Equity Calculator Does (and Doesn't) Do

This calculator helps you:

Structure an equity split conversation
See which founder is carrying what weight
Make invisible labor and risk visible
Use trust, time, and talent to shape your split

But it won't:

Give you legal advice
Tell you who's "right"
Replace a frank conversation with your cofounder
Predict how people will evolve over time

It's a compass, not a contract. Use it wisely.

How to Decide How Much Equity to Give a Cofounder

Equity sets tone, trust, and future power — it's never "just paperwork."
Equal doesn't always mean fair. Fair doesn't always mean equal.
Don't split until you understand what each founder is actually committing.
This calculator helps make that invisible work visible.
If you're scared to talk about it now — you're not ready to split anything.

Common Cofounder Equity Splits (With Examples)

There's no universal right answer, but these are real-world patterns that come up again and again:

50/50 — Two technical cofounders starting full-time on day one
60/40 — One cofounder quit earlier, built MVP, or brought funding
70/30 — Operator + capital vs a part-time support cofounder
90/10 — One person had the idea and traction; the other joined for long-term scaling
33/33/33 — Three cofounders with matching time, skill, and early commitment

These examples aren't formulas. They're conversation starters. Use our calculator to see where your real contributions lie.

Do You Actually Want a Cofounder?

Many founders default to "I should have a cofounder" because:

It's what YC or Techstars say
It's lonely
It feels safer

But bringing on a cofounder is a permanent relationship. Before you decide how much to give them, ask:

3 Questions That Matter:

Are you looking for skills — or emotional safety?
Is this person filling a gap? Or just making the journey feel less risky?
Would you still want them on the cap table in 5 years?
Even if they leave? Even if they disagree with you?
If you got hit by a bus, would you trust them to run the company?
If not, you may not have a cofounder. You may have a helper.

If you're not ready to answer those honestly, you're not ready to split anything.

Cofounder Equity Models (And When They Work)

There's no perfect formula. But there are 6 common models:

1. Equal Split (50/50)

Best when:

You started together, full-time, same day. No questions, no power imbalance.

Risk:

If one founder drifts or doesn't scale, resentment builds. Fast.

✅ Best for: Two technical cofounders starting same day, same burn, both full-time.

2. Weighted Split (Points-Based)

Best when:

You want to score the relationship across roles, risk, time, and value.

Risk:

Overcomplicating the early stage, or underweighting future risk.

✅ Best for: One founder bringing funding + IP, the other building day-to-day.

3. Founder Value Today vs Future

Best when:

One founder is doing the work now, the other is showing up later or in bursts.

Risk:

You may underestimate how valuable one founder becomes over time.

✅ Best for: Someone building now, someone critical once it scales (e.g. sales CEO).

4. Time-Based Cliff or Vesting

Best when:

You don't fully know if they'll commit — but want to create an option.

Risk:

They don't last. Then you're left with a messy breakup or wasted cap table space.

✅ Best for: You're not sure if they'll quit their job. This gives you an out.

5. Dynamic Equity Model (e.g. Slicing Pie)

Best when:

You're both contributing unevenly over time and want to track input precisely.

Risk:

Very few founders have the operational discipline to track time, capital, risk, and value consistently.

✅ Best for: Bootstrapped, distributed teams logging time, cash, and work over 6–12 months.

6. Buy-In or Silent Co-Founder

Best when:

Someone's bringing money, IP, or a network — but not full-time energy.

Risk:

You misread how much equity is worth when someone isn't in the trenches.

✅ Best for: Early angel, advisor, or operating partner giving capital or access — not time.

Cofounder Equity Calculator (Going Live Next Week)

This calculator isn't here to give you the answer. It's here to help you ask the real questions. You'll answer weighted questions about present and future contribution. Based on your answers, we'll suggest a starting point for equity discussion.

How it works

Answer each question honestly
Each slider reflects a key area of contribution or risk
Results are a conversation starter, not a verdict

This cofounder equity calculator gives you a structured starting point — not a final answer. Talk about the hard stuff. Let this guide the conversation.