25+ calculators for dilution, 409A valuations, stock options, SAFE notes, and runway — plus an instant AI verdict on whether your job offer's equity is any good.
Every tool runs in your browser — no account, no paywall on the math. Pick one and start.
Is your offer's equity above or below market? Instant AI analysis.
Side-by-side equity + salary across two offers.
Value your options and model exercise costs.
See your ownership across funding rounds.
Estimate fair market value for your strike price.
How many months until you raise again?
The only thing that costs money is an optional, one-time professional report. No subscription, ever.
✓ 30-day money-back guarantee. ✓ No recurring charges — you pay once and the report is yours.
No. FounderMath is free — all 25+ calculators work with no account. The only paid product is an optional $9.99 one-time Premium Equity Report. There's nothing to cancel because there are no recurring charges.
Enter the salary, equity, and terms from your offer letter. Our AI compares your equity against market benchmarks for your role and stage, flags red flags, and gives you a copy-paste negotiation script. Free, instant, no email required to start. Try it →
Your calculations never leave your browser. All math runs client-side in JavaScript. We don't store your financial data on any server.
A full professional equity report: visual dilution charts, personalized recommendations, a benchmark comparison, a cap-table health score, negotiation talking points, and an investor-ready PDF. One-time payment, lifetime access. Learn more →