Embed Free Startup Calculators

Add interactive equity, SAFE note, runway, and offer comparison calculators to your website. One line of code. Completely free.

Quick Start — 30 Seconds

Copy this code into any HTML page. That's it. No signup, no API key, no account.

<!-- Step 1: Add a container --> <div data-foundermath="dilution"></div> <!-- Step 2: Add our script --> <script src="https://founder-math.com/widget.js" async></script>

Equity Dilution Calculator Most Popular

See how founder equity changes across pre-seed, seed, Series A, B, and C funding rounds. Visual bar chart + dilution table.

Type: dilution Height: 520 Theme: light
<div data-foundermath="dilution"></div> <script src="https://founder-math.com/widget.js" async></script>

SAFE Note Conversion Calculator

Calculate how SAFE notes convert at Series A. Pre-money vs post-money SAFE, valuation cap vs discount, ownership and exit values.

Type: safe Height: 560
<div data-foundermath="safe"></div> <script src="https://founder-math.com/widget.js" async></script>

Startup Runway Calculator

Calculate how many months of runway are left based on cash, burn rate, and revenue growth projections.

Type: runway Height: 480
<div data-foundermath="runway"></div> <script src="https://founder-math.com/widget.js" async></script>

Co-Founder Equity Split Calculator

Help founders figure out a fair equity split based on each person's role, commitment, and capital contribution.

Type: equity-split Height: 580
<div data-foundermath="equity-split"></div> <script src="https://founder-math.com/widget.js" async></script>

Compare Startup Equity Offers

Side-by-side comparison of two startup job offers with total comp projection and winner declaration.

Type: compare-offers Height: 620
<div data-foundermath="compare-offers"></div> <script src="https://founder-math.com/widget.js" async></script>

Advanced Options

Customize the widget with data attributes.

<div data-foundermath="dilution" data-foundermath-height="400" data-foundermath-theme="light" data-foundermath-utm-source="your-site-name" ></div> <script src="https://founder-math.com/widget.js" async></script>

100% Free

No signup, no API key, no account. Copy code, paste it, done.

Works Everywhere

WordPress, Squarespace, Webflow, Notion, custom HTML — any site that allows iframes or scripts.

Lightweight

Widget pages load fast. No heavy frameworks. Pure HTML/CSS/JS under 20KB.

Auto-Updated

Calculators are hosted on our CDN. Any improvements automatically appear on your site.

Mobile Responsive

Adapts to any screen size. Your mobile visitors get the same great experience.

UTM Tracking

Add your source name for analytics. See exactly how much traffic the widget drives.