Venture Post
Startup Dilution Calculator
A priced funding round gives the new investor a percentage of the company and proportionally reduces everyone else’s ownership. Enter the pre-money valuation, investment, and current ownership split to see the post-money cap table.
Simple priced round
Existing ownership must total 100%. Values after the round are diluted pro rata.
The simple dilution formula
Post-money valuation equals pre-money valuation plus the new investment. The new investor’s ownership equals the investment divided by that post-money value. Every existing holder keeps the same proportion of the remaining ownership, which makes the dilution pro rata.
Example
A $2 million investment at a $10 million pre-money valuation produces a $12 million post-money valuation. The new investor receives 16.67%. Existing holders collectively retain 83.33%, so a founder who owned 70% before the financing owns about 58.33% afterward.
When this model is too simple
Real financings may convert SAFEs or notes, expand the option pool before closing, issue warrants, or use different fully diluted definitions. Those steps can shift dilution between founders, employees, and investors. This tool intentionally isolates one new-money priced round so the central calculation stays visible.
This is an educational scenario tool, not a cap-table record or legal advice.
Frequently asked questions
How is dilution calculated in a priced round?
New-investor ownership equals new investment divided by post-money valuation. Existing holders retain the remaining percentage pro rata.
Does this include SAFEs or an option-pool shuffle?
No. This version models a simple new-money priced round. Converting securities and pre-money option-pool increases require a cap-table model with additional terms.