Free Startup Calculator Tools

Interactive calculators for startup founders. No signup, no paywall, no email required. Just open and calculate.

Used by founders preparing for pre-seed, seed, and Series A fundraising.

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FounderMath Chrome Extension

A dilution calculator one click away — model funding rounds without leaving the page. Free, no permissions, all math runs in your browser.

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Founder Equity Score

Get your equity score in 60 seconds. Find out if your equity deal is fair compared to industry benchmarks for founders at your stage and role.

Equity Score Benchmark Shareable
Calculate Your Score →
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Startup Equity Checklist

Complete evaluation checklist for founders and employees. 34 checkpoints covering grants, vesting, taxes, dilution, exit scenarios, red flags, and negotiation.

Evaluation Checklist Negotiation
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Equity Tax Calculator

Estimate taxes on your startup equity. Compare ISO vs NSO tax, calculate AMT liability, decide on 83(b) election, and see your exact tax bill at exercise and sale.

Tax ISO vs NSO 83(b) AMT
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Equity Dilution Timeline

Watch your equity disappear across funding rounds. See exactly how much you lose at each round from pre-seed through Series C. Shocking visual timeline with dollar impact.

Dilution Visual Timeline
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Equity Dilution Calculator

See how your ownership percentage changes across pre-seed, seed, Series A, B, and C funding rounds. Visual stacked bar charts and detailed cap tables.

Dilution Funding Rounds Cap Table
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Free
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Co-Founder Equity Split Calculator

Figure out a fair equity split based on each founder's contributions: idea, technical skills, business expertise, time commitment, and capital invested.

Equity Split Cofounders Fair Split
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SAFE Note Calculator

Model Y Combinator SAFE note conversions. Compare pre-money and post-money SAFEs, see conversion prices, and understand dilution impact.

SAFE Notes Convertible Valuation Cap
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Startup Runway Calculator

Calculate how many months of runway you have left. Visualize your cash burn rate, project when you'll run out, and model hiring plans.

Runway Burn Rate Cash Flow
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Cap Table Builder

Build a complete cap table with founders, investors, option pool, and convertible notes. Track ownership percentages and share counts across rounds.

Cap Table Ownership Shares
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Vesting Schedule Calculator

Visualize your equity vesting schedule with cliff periods, monthly vesting, and acceleration. See how much equity you've earned at any point in time.

Vesting Cliff Timeline
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CAC/LTV Unit Economics Calculator

Calculate Customer Acquisition Cost, Lifetime Value, and LTV:CAC ratio. Understand whether your SaaS business model is fundamentally sound.

CAC LTV Unit Economics
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Free
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Startup Valuation Calculator

Estimate your startup's pre-money valuation using 3 proven methods: Berkus (pre-revenue), Scorecard (early stage), and Venture Capital (fundraising).

Valuation Berkus Pre-money
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Stock Option Calculator

Calculate what your startup stock options are really worth. See exit scenarios, vesting progress, and ISO vs NSO tax estimates in one place.

Stock Options ISO vs NSO Vesting
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Compare Equity Offers

Side-by-side comparison of two startup job offers. Input salary, options, strike price, vesting, and valuation — see which offer wins at every exit scenario.

Offer Comparison Total Comp Exit Scenarios
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Equity vs Salary Calculator

Compare two startup offers with different salary and equity mixes. See the break-even exit point where equity makes up for the salary difference.

Salary vs Equity Offer Comparison Break-Even Analysis
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Convertible Note Calculator

Model convertible note conversion at a priced round. See how interest, cap, discount, and maturity affect your equity.

Convertible Note Cap Discount
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Liquidation Preference Calculator

Model exit waterfall payouts with liquidation preferences. Compare 1x, 2x, participating preferred, and understand who gets paid first.

Exit Waterfall Liquidation Pref Participating
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Free Learning Resources

Startup Equity Checklist ✨

34 checkpoints to evaluate any equity offer. Grants, vesting, taxes, dilution, exits, and negotiation.

How Equity Dilution Works

Complete guide to understanding dilution across funding rounds.

SAFE Notes Explained

Everything founders need to know about YC SAFE notes.

SAFE Note Stacking

How multiple SAFEs convert with waterfall examples and ownership impact.

How to Calculate Runway

Step-by-step guide to understanding your startup's runway.

Vesting Schedules 101

Understand 4-year vesting, cliffs, and acceleration.

Cap Table Management

How to build and maintain a clean cap table.

Free Equity Cheat Sheet

Quick reference formulas for dilution, vesting, SAFE notes, and more.

Embed Calculators on Your Site

Free widgets for accelerators, blogs, and startup communities.

Frequently Asked Questions

Common questions about startup equity, dilution, and financing.

📊 Get Your Full Equity Dilution Report

See exactly how much equity you'll keep after pre-seed, seed, Series A, and beyond. Includes dilution charts, exit scenarios, and actionable recommendations.

Free Preview → Premium Report — $9.99

✓ Instant access   ✓ No subscription   ✓ Lifetime updates