Startup Equity Split Calculator

Startup equity split calculator allocates founder/team equity. Common splits: CEO 50%, CTO 30%, advisor 5%, employees 15%. Distribution from 1M total shares = 500k CEO, 300k CTO, 50k advisor, 150k employee pool. Foundational decisions matter - resentment from unequal splits kills more startups than competition.

Example: 1M total shares, CEO 50% (500k), CTO 30% (300k), advisor 5% (50k), employees 15% (150k). Reasonable for solo CEO with technical co-founder. Three equal co-founders model: 33/33/33 with 10% employee pool first. Slicing pie methodology accounts for differential contributions over time. Always vest 4 years with 1-year cliff.

Common equity allocation principles: (1) Equal among founding co-founders unless major disparity in commitment/risk/skills. (2) Reserve 10-15% for employees (option pool). (3) Advisors 0.25-1% each (advisor agreements typical). (4) Investors take 15-25% per round. Most disputes come from unequal splits without clear rationale - 60/40 splits often cause resentment when minor partner wants 50% later. Decide carefully and document with vesting schedule.

Quick example

With ceo equity of 50% and cto/co-founder equity of 30% (plus advisor equity of 5% and employee pool of 15%), the result is 500,000 / 300,000. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter CEO Equity %, CTO/Co-Founder Equity %, Advisor Equity %, Employee Pool %, and Total Shares Outstanding. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

What's happening under the hood

Equity split must total 100%. Each person's shares = total × their %. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

Where this fits in planning

This is a "what-if" tool, not a forecast. Use it to test ideas before committing: what happens if the rate is 2% lower than hoped, what happens if you add five more years. The value is in the scenarios you run, not the single answer you get from the defaults.

What this doesn't capture

Steady-rate math ignores real-world volatility. Actual returns are lumpy; sequence-of-returns risk matters most in drawdown; fees and taxes drag on compound growth; and behaviour changes in drawdowns can reduce outcomes below the projection. The number represents one scenario rather than a forecast.