Semantic Version (SemVer) Calculator
Compare versions and test npm ranges.
Runs 100% in your browser — nothing is ever uploaded.
What is SemVer Calculator?
Compare semantic versions, validate version strings and test npm-style ranges like ^1.2.3 or ~2.0.0 instantly. Free and 100% in your browser. Enter a value and watch the result update instantly — no waiting and no page reloads. Free and unlimited, with no watermarks and no registration — all processing happens right in your browser, so nothing is ever sent to a server.
How to use SemVer Calculator
- Open SemVer Calculator — it runs instantly in your browser.
- Enter your value or adjust the interactive controls.
- The result updates in real time as you type.
- Copy the result with one click and use it anywhere.
Frequently asked questions
Is SemVer Calculator really free?
Yes — SemVer Calculator is 100% free with no limits, no watermarks and no registration. You can use it as often as you like, on as many files or inputs as you need.
Is my data safe when I use SemVer Calculator?
Absolutely. SemVer Calculator runs entirely in your browser using JavaScript — your input is processed on your own device and is never uploaded to any server.
Does SemVer Calculator work on mobile devices?
Yes. SemVer Calculator works in any modern browser on desktop, tablet and mobile (Chrome, Firefox, Safari, Edge) — there is no app to install.
Is it safe to generate passwords in a browser?
Yes — we use the Web Crypto API (crypto.getRandomValues), the same cryptographically secure randomness source used by password managers. Generation happens on your device and nothing is transmitted or stored.
Do you see the JWT tokens I decode?
No. Decoding is pure client-side Base64 parsing — the token never leaves your browser. Still, avoid pasting production secrets anywhere as a general habit.
Are the UUIDs really unique?
UUID v4 has 122 random bits — the collision probability is so small it is negligible for any real-world system. We use the native crypto.randomUUID() implementation.