Understand your startup equity before it's too late
Interactive calculators that turn confusing dilution, SAFE notes, and runway math into beautiful visualizations. See exactly what happens to your ownership.
See your dilution in real-time
Drag the sliders and watch what happens to your equity as you raise money.
Equity Dilution Simulator
What founders say about FounderMath
"I was about to accept a term sheet without understanding how multiple SAFE notes would dilute me. FounderMath showed me I'd lose 8% more than I thought. Negotiated better terms."
"The dilution calculator saved my cofounder relationship. We had very different expectations about how much equity we'd each have after our seed round. Seeing the numbers made it easy to agree."
"I used 3 different equity calculators before finding FounderMath. This is the only one that actually shows what happens with multiple funding rounds. Clear, accurate, fast."
Popular Calculators
The tools founders use most to understand their equity and plan their next round.
Equity Dilution
See how your ownership changes across funding rounds
#1 Most UsedSAFE Note Calculator
Model pre-money and post-money SAFE conversions
#2 Most UsedRunway Calculator
Calculate how long your cash will last
#3 Most UsedVesting Schedule
Visualize your equity vesting over time
Compare Offers
Side-by-side equity offer comparison
Cap Table Builder
Track founders, investors, and option pools
Funding Scenario Comparison
Compare two funding scenarios side-by-side. See how different valuations affect your equity.
New409A Valuation Estimator
Estimate common stock FMV and option strike prices. Understand the discount to preferred stock.
NewFree Equity Dilution Report
Get a personalized report showing how your equity dilutes across rounds. Takes 30 seconds.
Free ReportPremium Equity Report
Professional PDF report with multi-round projections, dilution charts, and investor-ready formatting. $9.99 one-time.
$9.99 One-TimeEquity Benchmarks 2026
Data on founder ownership at every stage. Dilution rates, option pools, and IPO benchmarks.
New Research20 startup tools, one clear picture
Founder Equity Score
NEW: Is your equity deal fair? Get an instant 0-100 score compared to industry benchmarks. Takes 60 seconds. Free.
Offer Letter Analyzer
NEW: Paste your startup offer letter. Instantly find red flags, missing clauses, and negotiation opportunities. 100% free and private.
Dilution Timeline Visualizer
NEW: Watch your equity disappear across funding rounds. See exactly how much you lose at Pre-Seed, Seed, Series A-C. Shocking results guaranteed.
Equity Dilution Simulator
See how your ownership changes across multiple funding rounds. Visualize pre-money and post-money valuations, investor shares, and founder dilution.
Co-Founder Equity Split
Get a fair, data-driven equity split based on each founder's contributions. Rate idea, tech skills, business expertise, and more.
Runway Calculator
How many months until you run out of cash? Factor in revenue growth, burn rate changes, and one-time expenses to plan your next raise.
SAFE Note Converter
Understand what your SAFE converts to. Calculate conversion price, share count, and investor ownership for cap and discount scenarios.
CAC/LTV Unit Economics
Are your unit economics working? Input your acquisition costs, churn rate, and revenue per customer to see if your business model is sustainable.
Vesting Schedule Visualizer
Map out your vesting schedule with cliff periods, acceleration triggers, and early exercise options. See exactly when you earn each slice of equity.
Cap Table Builder
Build your cap table from scratch. Add founders, investors, option pools, and SAFEs. See ownership at every stage of your company's journey.
Startup Valuation Calculator
Estimate your startup's worth using 3 proven methods: Berkus, Scorecard, and Venture Capital. Get a defensible valuation in 2 minutes.
Stock Option Calculator
Find out what your startup stock options are really worth. See exit scenarios, vesting progress, and ISO vs NSO tax estimates.
Compare Equity Offers
Got two startup job offers? Compare them side-by-side. See total compensation, equity value, and upside at different exit valuations.
Is My Equity Offer Good?
Take a 5-question quiz to find out if your equity offer is above or below market rate for your role and stage.
Funding Scenario Comparison
Compare two funding scenarios side-by-side. See how different valuations, round sizes, and option pools affect your equity.
409A Valuation Estimator
Estimate your startup's common stock fair market value and option strike prices using backsolve, scorecard, and Berkus methods.
Startup Exit Calculator
NEW: Model your equity payout at different exit valuations. See how liquidation preferences, dilution, and exit multiples affect your take-home.
Free Equity Dilution Report
Get a personalized report showing how your equity dilutes across funding rounds. Includes benchmarks, recommendations, and exit value projections.
Equity vs Salary Calculator
Compare a startup job offer with equity against a corporate salary position. See the break-even exit valuation and make the right career choice.
Equity Story Generator
Create a compelling equity narrative for cofounders, investors, or employees. Visualize the journey from startup to exit with clear projections.
Equity Tax Calculator
NEW: Estimate taxes on your startup equity. Compare ISO vs NSO, calculate AMT liability, and decide whether to file an 83(b) election.
From confused to confident in 3 steps
Pick a Calculator
Choose from 19 startup-specific tools. Each one solves a specific math problem founders face.
Adjust Your Numbers
Input your real numbers with intuitive sliders and fields. Watch the visualization update in real-time.
Understand & Share
Get instant clarity on your equity situation. Save scenarios, compare side-by-side, and share with cofounders.
Start free, upgrade when you need more
Free
- All 20 tools
- Basic inputs & outputs
- Interactive charts
- Save scenarios
- Export PDF/PNG
- Side-by-side comparison
Pro
- All 20 tools
- Advanced inputs & outputs
- Interactive charts
- Save unlimited scenarios
- Export PDF & PNG
- Side-by-side comparison
- Multi-round simulation
- SAFE conversion waterfall
Team
- Everything in Pro
- Share with up to 5 members
- Collaborative editing
- Embeddable charts
- Custom branding on exports
- 15+ round simulation
- Priority support
📊 Free Equity Cheat Sheet
Quick reference formulas for dilution, vesting, SAFE notes, runway, and LTV:CAC. Print it out and keep it on your desk.
Download Free Cheat Sheet →Stop guessing about your equity
Understand your ownership, plan your raises, and negotiate better deals with interactive visualizations.
Try the Calculator FreeComparing equity tools? See Carta vs Pulley vs FounderMath