What is Startup Equity Calculator?
Startup Equity Calculator is a free, browser-based tool in the Crypto & Finance Tools suite. Model the value of startup employee equity: enter your option grant (shares, strike price), the company's latest 409A valuation, expected exit valuation, and future dilution. See net proceeds, ROI, and effective ownership at exit.
The headline benefit: estimate the value of your employee stock options after dilution and exit.
Unlike most online tools that upload your file to a server, process it, and send it back, Startup Equity Calculator runs entirely in your browser. Open DevTools → Network while using it and you'll see zero file-upload requests — only static assets (JavaScript, CSS, fonts) load. Your data never leaves your device.
Why use this startup equity calculator?
Three reasons EasyFileKit's Startup Equity Calculator stands out from the crowd:
- **Private by design** — all processing happens locally via JavaScript and WebAssembly. No server ever sees your input.
- **Instant** — no upload wait, no queue, no server round-trip. Results appear the moment you act.
- **Free & unlimited** — no accounts, no watermarks, no daily caps. Use it as many times as you like.
How to use Startup Equity Calculator — step by step
Here's the complete walkthrough. Everything happens instantly in your browser:
- **Step 1.** Enter your option grant: number of shares and strike (exercise) price.
- **Step 2.** Enter the company's current fully-diluted share count and latest 409A valuation.
- **Step 3.** Set an expected exit valuation and additional dilution from future rounds.
- **Step 4.** Read your proceeds, ROI, and effective ownership at exit.
That's it. No sign-up, no upload bar, no waiting. If something doesn't work as expected, check the FAQ below.
Common use cases for Startup Equity Calculator
People reach for Startup Equity Calculator in a few recurring situations:
- When you need the result **now** and can't wait for a server-based tool to upload, queue, and process your file.
- When your file is **private or sensitive** — financial documents, personal photos, medical PDFs — and you don't want it travelling across the internet.
- When you're on a **slow or metered connection** — uploading a 50 MB file just to compress it makes no sense when the same work can happen locally.
- When you've hit the **daily limit or paywall** on another "free" tool site.
Privacy: what actually happens to your data
This is the single most important point about Startup Equity Calculator, so it deserves its own section.
When you use this tool, your input is processed by JavaScript running in your browser tab. The code is downloaded once (cached afterwards) and executes locally on your CPU. At no point is your file, your text, or your input data transmitted to any server.
You can verify this yourself in under 30 seconds:
- Open Startup Equity Calculator in your browser.
- Press F12 to open DevTools.
- Switch to the Network tab and tick "Disable cache".
- Use the tool — drop a file, type text, whatever the tool needs.
- Watch the Network log. You'll see only static assets (JS, CSS, fonts, icons). No request contains your data.
This isn't a setting you toggle or a promise in a privacy policy — it's how the tool is architecturally built. There is no upload endpoint to call.
Frequently asked questions about Startup Equity Calculator
Q: What is the strike price?
A: Also called the exercise price — the per-share price you pay to convert options into shares. It's set by the company's 409A valuation at grant time and doesn't change.
Q: What's the difference between options and RSUs?
A: Options give you the right to buy shares at the strike price — you only profit if the share value rises above it. RSUs (Restricted Stock Units) are granted at no cost — they're worth the full share value at vesting.
Q: How does future dilution affect my payout?
A: Each new funding round issues new shares, diluting everyone proportionally. If you own 1% today and the company raises 3 more rounds each diluting 20%, your final ownership is 1% × 0.8 × 0.8 × 0.8 = 0.512%.
Q: Does this account for taxes or exercise costs?
A: We show gross proceeds (exit value − strike cost). Actual taxes depend on your grant type (ISO/NSO/RSU), holding period, and jurisdiction — often 20-50% of the gain. Consult a tax advisor before exercising.
Q: What if the exit value is below my strike?
A: Your options are “underwater” — exercising would lose money. You'd simply not exercise, and the options expire worthless. Most employee options have a 10-year expiration window.
Q: Are my equity details uploaded?
A: No. The math runs 100% in your browser. Refresh to clear — your grant details are sensitive, treat them accordingly.
Startup Equity Calculator: EasyFileKit vs server-based tools
Most "free" online tools that do what Startup Equity Calculator does follow the same model: you upload your file to their server, they process it with a backend script, then they send the result back. Here's the honest comparison:
| | EasyFileKit | Server-based tools |
|---|---|---|
| **Your file leaves your device?** | Never | Yes, uploaded to a server |
| **Speed** | Instant (no upload) | Slower (upload + queue + download) |
| **Privacy** | Complete | Your file is on someone else's computer |
| **Cost** | Free, unlimited | Often capped or "premium" gated |
| **Works offline** | Yes (PWA) | No |
Server-based tools aren't evil — they exist because some tasks genuinely need heavy backend compute. But for everything Startup Equity Calculator does, client-side processing is strictly better for you.
Under the hood: how Startup Equity Calculator works
Startup Equity Calculator is built with modern browser APIs. Depending on what it does, it may use:
- **Canvas API** — for image manipulation (pixel-level access, filters, resizing).
- **Web Crypto API** — native, hardware-accelerated cryptography (AES-GCM, SHA-256, PBKDF2) for any encryption or hashing.
- **pdf-lib / pdf.js** — fully client-side PDF creation and rendering.
- **MediaRecorder API** — for capturing screen, audio, and video.
- **WebAssembly** — for heavy codecs (image compression, media processing).
All of these run inside your browser's sandbox. They cannot access your filesystem (beyond files you explicitly choose), cannot make network requests with your data, and cannot run persistently in the background.
Pro tips for getting the most out of Startup Equity Calculator
- **Bookmark the tool** — it works offline once cached, so you can use it even without a connection.
- **Install EasyFileKit as a PWA** — open the browser menu and choose "Install app" for a standalone window and offline access.
- **Use it on mobile** — every tool is fully responsive and works on phones and tablets, not just desktops.
- **No file size anxiety** — because nothing uploads, you can process large files that server-based tools would reject or charge for.
Try Startup Equity Calculator now
The tool is right above this article — scroll up and start using it. No sign-up, no upload, no limits.
If you found Startup Equity Calculator useful, explore the rest of the Crypto & Finance Tools suite — there are more tools that work the same private, instant, free way. And if you have a question that isn't covered in the FAQ above, the About page has our contact email.