Can I use UUIDs as database primary keys?

Yes, commonly — they avoid needing centralized ID coordination across distributed systems, though they take more storage than sequential integers and can affect index performance in some databases.

Version 4 of the UUID spec, which generates IDs using random numbers — other versions use timestamps or namespace-based hashing instead.

Is a UUID the same as a GUID?

Yes, effectively — GUID (Globally Unique Identifier) is Microsoft's term for the same 128-bit identifier format standardized as UUID in the IETF RFC.

How many UUIDs can I generate at once?

Up to 50 per batch — enough to quickly seed test data or placeholder records without generating an unwieldy list.

Does it generate a UUID automatically when the page loads?

Yes — one UUID is generated as soon as the tool loads, before you click Generate at all.

What if I enter 0 or a negative number for how many?

It's clamped to a minimum of 1 — you'll always get at least one UUID regardless of what's entered in the count field.

Are the UUIDs generated using a real cryptographic random source?

Yes — via the browser's crypto.randomUUID(), which draws from the same secure random number generator behind crypto.getRandomValues(), not a simple pseudo-random function like Math.random().

Can two different visitors ever generate the same UUID?

In practice, no — with 122 random bits per UUID, the chance of any collision, even across huge numbers of generations worldwide, is astronomically small.

UUID Generator

About the UUID Generator

Generates one or many random UUIDs (Universally Unique Identifiers) in the standard version-4 format, commonly used as unique IDs for database records, API resources, and distributed systems.

100% Free Runs in Your Browser No Sign-Up Required

How to use it

Enter How many UUIDs to generate.
Click Generate.
Copy any UUID with its copy button.

Formula

Uses your browser's crypto.randomUUID() function, generating a 128-bit value formatted as 32 hex digits split into 5 groups, with fixed bits marking it as version 4.

Worked example

A typical generated UUID looks like f47ac10b-58cc-4372-a567-0e02b2c3d479.

Recommendations

• The collision probability for two random v4 UUIDs is astronomically small — practically safe to treat as unique without central coordination.
• Generate multiple at once to quickly seed test data or placeholder records.
• UUIDs aren't sequential or sortable by creation time — a timestamp-prefixed ID scheme would suit that need better.

Frequently asked questions

Version-4 UUIDs have 122 random bits, giving an astronomically low collision probability — billions would need generating before duplicates became a practical concern.

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