Free UUID Generator
Generate secure UUIDs in your browser. Create, validate, copy, download and format UUIDs. No login. No upload.
Everything happens in your browser — UUIDs are generated locally with your browser's secure crypto, never on a server. Nothing is uploaded, stored, or tracked.
Generate
UUID v4 (Random)Statistics
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Download
History
Keeps your last 20 generations on this device only (localStorage). Off by default.
No history yet.
Validate & inspect
Format
Convert the UUID above between cases and hyphenated/compact forms.
Nil UUID
The nil UUID is all zeroes. It's a valid placeholder that represents "no value" — handy for default columns, sentinel keys, or tests where you need a UUID-shaped value that isn't real.
00000000-0000-0000-0000-000000000000
GUID? On Windows / .NET, "GUID" is Microsoft's name for the same 128-bit value — the UUIDs here work anywhere a GUID is expected (just watch casing, since .NET often uppercases them).
Generate UUIDs in your code
How to create UUIDs natively in each language / database.
What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID on Windows, is a 128-bit value written as 32
hexadecimal digits in the pattern 8-4-4-4-12. It's designed so that anyone can generate one
independently and it will still be unique in practice — no central authority or coordination required.
When should you use UUIDs?
Use UUIDs when IDs must be created without a central sequence: distributed systems, offline-first apps, merging data from multiple sources, public identifiers you don't want to be guessable, or test fixtures. They let different services mint IDs at the same time without collisions.
UUID vs auto-increment IDs
Auto-increment integers are compact and sortable but require a single database to hand them out, leak row counts, and are trivially guessable. UUIDs trade a little size and sortability for independence and unpredictability — any client can generate one safely, which is why they're common for public-facing keys.
UUID version 4
Version 4 UUIDs are almost entirely random: 122 random bits plus fixed version and variant markers. With that much entropy, the chance of a collision is negligible for any realistic number of IDs, which is why v4 is the default choice when you just need a unique identifier.
Why browsers can generate secure UUIDs
Modern browsers expose a cryptographically secure random number generator via the Web Crypto API
(crypto.randomUUID() and crypto.getRandomValues()). This tool uses it directly, so
UUIDs are generated on your device with real cryptographic randomness — never the predictable
Math.random(), and never a server.
Your data stays in your browser
This tool uses your browser's built-in APIs. Nothing is uploaded, stored, logged, or tracked. History is optional and lives only on this device. There is no account, no watermark, and no external service — you can even use it offline.
Built by Balance On Hand
Free tools with no login, no upload, and no unnecessary friction — plus a cash-flow planning app that helps you see how bills, subscriptions, loans, income, and spending affect your future balance.