Are these UUIDs unique?

UUID v4 uses 122 random bits, making collisions astronomically unlikely (one in 5.3 × 10^36). For practical purposes, they're unique.

Are they cryptographically secure?

Yes. The tool uses crypto.randomUUID() (or crypto.getRandomValues as a fallback), which draws from the browser's cryptographically-secure random source.

What's the difference between v4 and other UUID versions?

v4 is random. v1 is time + MAC address-based, v3 and v5 are name+namespace hashed. v4 is the right choice for almost all general-purpose uses.

Can I generate UUIDs without hyphens?

Yes — uncheck 'Include hyphens' to get a 32-character hex string. Toggle 'Uppercase' for uppercase hex.

Is there a limit on how many I can generate?

The UI caps at 100 per click to keep the page responsive. You can click Generate as many times as you like.

UUID Generator

Generate cryptographically-secure UUID v4s — bulk & instant.

100% private — no uploads Developer ToolsFree & unlimited Read tutorial

See how it works

Watch a quick simulation of this tool in action — no file needed.

How to use UUID Generator

Follow these steps — everything happens instantly in your browser.

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Step 1. Set how many UUIDs you want (1 – 100).
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Step 2. Toggle uppercase or hyphen-free output if you need a different format.
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Step 3. Click Generate UUIDs.
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Step 4. Copy individual IDs or all of them with the Copy all button.