Before you start
What you need
Two to twenty founders with relative weights and an option-pool percentage.
Finance & Business Finance
Startup Equity Split Calculator
Explore a founder ownership split from relative contribution weights after reserving an employee option pool.
- 01Private browser calculation
- 02Assumptions stay visible
- 03CSV and print ready
Transparent method
How this calculation works
The option pool is reserved first. Remaining founder equity is allocated in proportion to each positive weight.
Useful output
What you receive
Founder ownership percentages, option pool, weight table, assumptions, and CSV.
Decision guardrail
What this does not decide
Weights are subjective planning inputs. Ownership affects control, tax, incentives, and legal rights beyond percentage math.
Practical uses
Where this tool helps
- Facilitate a founder discussion.
- Test different option-pool sizes.
- Document a preliminary split scenario.
Data boundary
Financial inputs remain local
Calculations and report generation run in your browser. Nirmion does not upload, retain, or recover the values entered here. The public catalogue request contains only the tool slug.