Free online tool
UUID Generator
Generate v4 UUIDs one at a time or in bulk. Cryptographically random, fully offline.
What a UUID is
A UUID (Universally Unique Identifier) is a 128-bit value formatted as five hyphen-separated groups. Version 4 UUIDs are generated from random bits, which makes them collision-resistant in practice — the chance of generating the same one twice, even at astronomical scale, is vanishingly small. That's what makes them the default choice for primary keys, session IDs, correlation IDs, and any identifier you want to be safely unique without coordinating with a central authority.
How this generator works
The tool uses the browser's native crypto.randomUUID when available, and falls back to the same underlying cryptographic RNG on older browsers. Nothing is sent to a server — every ID is generated locally, which means you can safely use the output as production identifiers.
+Are v4 UUIDs really unique?
In the mathematical sense, no — but the odds of a collision are so low (about 1 in 2^122) that they're treated as unique in every serious system.
+What's the difference between v1, v4 and v7?
v1 is based on timestamp and MAC address, v4 is fully random, and v7 is a newer time-ordered variant. v4 is the safest default for privacy and general use.
Why use the UUID Generator on ToolNest?
The UUID Generator is one of more than forty free browser-based utilities we maintain on ToolNest. Every tool on the site is engineered around the same three promises: it must be fast, it must protect your privacy, and it must be genuinely useful without hiding features behind an account, a paywall, or an email capture form. Whether you use the UUID Generatoronce a month or several times a day, it should feel like a native part of your workflow — open the tab, get the result, move on.
Everything happens directly inside your web browser. When you type, paste, or upload something into the UUID Generator, that data never leaves your device. There is no server round-trip, no logging, no analytics pixel watching your keystrokes, and no third-party API silently receiving a copy of your input. Closing the browser tab is the same as clearing your session. This is a deliberate design choice: too many free "online tools" quietly funnel user content through remote servers, and we do not think a utility as small as this one justifies that risk.
Speed is the other pillar. The UUID Generator loads on a cold connection in well under a second and stays responsive on older phones, low-power laptops, and metered mobile networks. There are no heavy frameworks layered on top of the tool, no autoplay video ads, and no blocking third-party scripts. Search engines like Google reward pages that load quickly and stay interactive, but more importantly, so do human visitors who came here to get one specific job done.
If the UUID Generator saves you time, the best thing you can do is bookmark this page and share it with a colleague or classmate who might need it. We also welcome direct feedback — bug reports, feature requests, and suggestions for entirely new tools all go to the same inbox and are read by a human. The best tools on ToolNest started life as a one-line reader email, and this page will keep improving as long as people keep telling us what they wish it did better.