In short: A UUID is a 128-bit identifier written as 36 characters like 3f2b…-4…; version 4 UUIDs are random and version 7 UUIDs start with a timestamp so they sort by creation time.
About UUID Generator
A UUID (universally unique identifier, also called a GUID) is a 128-bit value written as 32 hex digits in five groups, like 3f2b8c1e-9a4d-4e7b-b2c1-7d5e0a9f1c23. You can create them anywhere, without a central counter, and still be confident that two will practically never collide (a random version 4 UUID has 122 random bits) — which is why they are popular as database keys, request IDs and file names.
Version 4 UUIDs are 122 bits of randomness. Version 7, standardized in RFC 9562, puts a millisecond timestamp in the first 48 bits so the values sort by creation time, which keeps database indexes compact. This generator uses crypto.getRandomValues, the same secure source browsers use for cryptography, and can also check whether a string is a valid UUID and tell you its version.
How to use UUID Generator
- Choose v4 for pure randomness or v7 if you want IDs that sort by time.
- Set how many you need (up to 5,000) and the output format.
- Press Generate, then copy them all or download a text file.
- To check an existing value, paste it into Validate a UUID.
Examples
v7: 01926f3e-5c2a-7b41-9e3d-2f8a6c1b0d47. The first part encodes the creation time, so newer rows come later in an index.
Generate 100 v4 UUIDs in uppercase without hyphens and paste them into a CSV for seed data.
Frequently asked questions
Can two UUID v4 values ever be the same?
In theory yes, in practice no. You would need to generate about 2.7 quintillion UUIDs to have a 50% chance of a single duplicate.
Should I use v4 or v7?
Use v7 for database primary keys, because time-ordered values insert efficiently into B-tree indexes. Use v4 when the ID must not reveal when it was created.
Are these UUIDs generated on a server?
No. They are created in your browser with the Web Crypto API, and nothing is recorded.
Is GUID the same as UUID?
Yes. GUID is Microsoft’s name for the same 128-bit format. Some Windows tools display GUIDs in braces and uppercase, which you can pick in the format menu.
Updated November 2026 · Free, no signup · How we build and test tools