Startup equity split
calculator
Equity conversations are hard. This tool makes them objective. Rate each co-founder's contributions across 7 weighted factors to find a fair split — then share the results.
| Factor | Weight | Founder 1 | Founder 2 |
|---|---|---|---|
| Idea Originator | 10% | ||
| Domain Expertise | 12% | ||
| Technical Execution | 20% | ||
| Business & Sales | 18% | ||
| Full-time Commitment | 15% | ||
| Capital Contribution | 13% | ||
| Risk Taken | 12% | ||
| Equity Share | 50.0% | 50.0% | |
How this works: Each factor is weighted by its typical importance to an early-stage startup. Technical execution (20%) and business/sales (18%) carry the most weight because they drive product-market fit. Adjust scores to reflect each founder's actual contribution — not promises, not potential, but what they're doing today.
Share this split with your co-founders
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How to split equity between co-founders
Equity splits are one of the most important — and most contentious — decisions in a startup's early days. Research from the Kauffman Foundation found that founding teams who split equity based on contribution (rather than equal splits) performed significantly better.
The default 50/50 split feels fair, but it rarely is. One founder almost always contributes more in some dimensions — technical execution, business development, capital, or risk. An unequal split that reflects reality prevents resentment later.
This calculator weights seven factors by their typical importance to early-stage startups. Technical execution (20%) and business/sales (18%) carry the most weight because they're what actually get a product to market. Ideas (10%) are weighted least — because ideas are cheap, execution is everything.
The 7 factors that determine fair equity
- Idea Originator (10%) — Who conceived the core concept? Important, but execution matters far more.
- Domain Expertise (12%) — Industry knowledge, relevant network, and credibility in the space.
- Technical Execution (20%) — Who actually builds the product? The highest-weighted factor for a reason.
- Business & Sales (18%) — Revenue generation, customer acquisition, partnerships, and go-to-market strategy.
- Full-time Commitment (15%) — A part-time founder shouldn't get the same equity as someone who quit their job.
- Capital Contribution (13%) — Money invested matters, but it's not a substitute for sweat equity.
- Risk Taken (12%) — Leaving a $300K job to work on an unfunded startup is a real contribution.
What if you don't need a co-founder?
The biggest equity negotiation is the one you never have. Solo founders who use an AI co-founder keep 100% of their equity while getting 24/7 technical execution, strategic thinking, and autonomous shipping. At $499/month, it costs less than 0.3% of a typical technical co-founder's first-year compensation — and takes exactly 0% of your company.