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 for startup valuation calculator queries.
Fundraising calculators
Model SAFE conversion, convertible note conversion, and cap-versus-discount scenarios with transparent assumptions.
Cap table calculators
Understand founder dilution, equity dilution, and option-pool shuffle effects from financing rounds.
Current calculators
Simple Pre/Post-Money Calculator
Enter pre-money plus ownership sold, raise amount, or post-money and solve the remaining deal terms instantly.
Open calculator →Full Pre/Post-Money Valuation Calculator
Translate between investment amount, valuation, ownership, price per share, and optional share counts.
Open calculator →SAFE Conversion Calculator
Estimate the conversion price and shares from valuation caps and discounts at a priced round.
Open calculator →Convertible Note Calculator
Estimate note principal plus interest, conversion price, note shares, and implied ownership.
Open calculator →Founder Dilution Calculator
See how new money and option pool top-ups reduce founder ownership percentages.
Open calculator →Option Pool Calculator
Estimate option pool top-ups and compare pre-money versus post-money pool treatment.
Open calculator →How to use FounderMath in a fundraising week
- Anchor the priced-round story with the valuation calculators.
- Layer SAFE or note overhang with the fundraising tools.
- Check founder ownership and pool expansion on the cap-table tools.
- Read methodology and sources before treating any output as a planning baseline.
FAQ
What calculators does FounderMath include?
FounderMath currently covers simple and full pre/post-money valuation, SAFE conversion, convertible notes, founder dilution, and option pool sizing with educational assumptions.
Is FounderMath free to use?
Yes. The calculators are free, no-login educational tools. They are not a substitute for legal, tax, accounting, or fundraising advice.
Where should I start if I only know the raise size?
Start on the Simple Pre/Post-Money Calculator for percent-sold math, then use the full valuation calculator if you need share price and investor shares.
Does FounderMath store my cap table?
No. Calculations run in the browser for educational estimates. Do not paste confidential company or investor data you are not comfortable putting in a browser form.
Last reviewed September 7, 2026.