Free Online UUID Generator (v4)

A UUID is a 128-bit identifier written as 32 hex digits in five groups, 8-4-4-4-12, for 36 characters in total. RFC 9562 defines it. Version 4, which this tool makes, fills 122 of the bits at random.

Only version 4, the random kind, using your browser's crypto.randomUUID. Every ID has a 4 as the first digit of the third group. There is no v1, v7, nil UUID or ULID option yet, so use a library for those.

None in the value. GUID is Microsoft's name for a UUID, and .NET's Guid.NewGuid makes the same random version 4 IDs. GUIDs are often shown in uppercase inside braces. Tick Uppercase and With braces to get {3F2B9C1E-7A4D-4E8B-9C2F-5D6E7F8A9B0C}.

In theory yes, in practice no. There are about 5.3 x 10^36 possible v4 UUIDs, so you would need around 2.7 quintillion of them for a 50% chance of one repeat. A Node test of one million found no duplicates.

v7 starts with a timestamp, so new keys sort in time order and keep B-tree indexes compact. v4 is fully random, which spreads inserts across a large index. This tool makes v4 only, which suits most tables and IDs that must not reveal when they were made.

Type a number from 2 to 100 in the Bulk Generate box and click the button next to it. Every UUID uses the format options you ticked. Copy All copies the list with one UUID per line. For more than 100, run it again and paste again.

Yes. Tick No hyphens before you click Generate, and you get 32 hex characters, such as 3f2b9c1e7a4d4e8b9c2f5d6e7f8a9b0c. It is the same 128-bit value, and most languages and databases accept it.

Format options apply when the next UUID is made, not to the one already on screen. Tick Uppercase, With braces or No hyphens first, then click Generate or the bulk button again to get IDs in the new format.

It won't be guessable, since crypto.randomUUID uses the browser's secure random source and gives 122 random bits. Still, UUIDs are meant as IDs and often end up in logs and URLs. For API keys or passwords, use our password generator with 32 or more characters.

The count box corrects itself on every keystroke and keeps the number between 2 and 100. Deleting the number sets it to 2, and anything above 100 becomes 100. Use the arrows on the box to set the count you want.

Yes. It's free with no sign-up and no daily limit. UUIDs are created in your browser tab and are not saved or sent to us. The only usage data sent is a Generate or Copy click and how long a run took, with no UUID in it.