Startup fundraising math without the spreadsheet fog.
FounderMath is a static-first utility site for founders who need fast educational estimates for valuation, dilution, SAFE conversion, and convertible note scenarios.
Quick answer
What is FounderMath?
FounderMath is a no-login educational calculator site for startup finance math. It helps founders estimate pre-money and post-money valuation, percent sold, SAFE conversion, convertible note conversion, founder dilution, and option-pool effects from explicit assumptions.
Use the calculator pages for quick outputs and the methodology and sources pages to inspect formulas, limitations, and source categories. FounderMath is not legal, tax, accounting, investment, fundraising, or cap-table administration advice.
Calculator topic hubs
Valuation calculators
Estimate pre-money, post-money, investment ownership, and simple percent-sold math.
Fundraising calculators
Model SAFE conversion, convertible note conversion, and future financing terms with transparent assumptions.
Cap table calculators
Understand founder dilution and cap table changes from financing rounds and option pools.
Current calculators
Simple Pre/Post-Money Calculator
Enter pre-money and post-money valuations to estimate the percent sold, without share inputs.
Full Pre/Post-Money Valuation Calculator
Translate between investment amount, valuation, ownership, and optional share counts.
SAFE Conversion Calculator
Estimate the conversion price and shares from valuation caps and discounts.
Convertible Note Calculator
Estimate note principal plus interest, conversion price, note shares, and implied ownership.
Founder Dilution Calculator
See how new money and option pool top-ups reduce founder ownership.
Option Pool Calculator
Estimate option pool top-ups and compare pre-money versus post-money pool treatment.