UUID vs GUID
UUID and GUID are the same 128-bit identifier. Learn the naming, formatting differences and how to convert between them.
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UUID vs GUID
UUID is the IETF / RFC name. GUID is the Microsoft name. The bits are the same. Differences you will see in the wild are braces, uppercase hex and string formats such as "D", "N" and "B" in .NET.
Worked example: One identifier, two names
Both forms
UUID: 550e8400-e29b-41d4-a716-446655440000
GUID: {550E8400-E29B-41D4-A716-446655440000}Same 128 bits
✓ Valid UUID Version: 4 — random Variant: RFC 9562 (10xx)
Practical tip
When an API says “send a GUID”, a standard UUID string is almost always accepted. Only add braces if the docs show them.
How to use this UUID Generator
- 1Use the live tool above — it runs entirely in your browser and never uploads your data.
- 2Paste the sample from the worked example, or use your own input.
- 3Copy the result, then adapt the same steps in your editor, script, or pipeline.
UUID vs GUID FAQs
Can I use a UUID where a GUID is required?
Yes. Pass the same hex groups. Add braces only if the receiver is a picky Windows API.
Which RFC defines UUIDs now?
RFC 9562 (2024) obsoletes RFC 4122 and adds versions 6, 7 and 8 plus the Max UUID.
More UUID Generator pages
- UUID v4 Generator OnlineGenerate random UUID v4 values online. Cryptographically secure, RFC 4122 / RFC 9562 compatible, free and private in your browser.
- UUID v7 GeneratorGenerate time-ordered UUID v7 values (RFC 9562). Better as database primary keys than random UUID v4 because they sort by creation time.
- GUID Generator OnlineGenerate a GUID online in the Windows {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX} format or as a plain UUID. Free, no signup.
- UUID Validator OnlineValidate a UUID or GUID online. Check the 8-4-4-4-12 shape, version nibble and RFC variant, including the Nil UUID.
- Generate a UUID Without HyphensGet a UUID as 32 hex characters with no hyphens. Useful for filenames, tokens and systems that reject the dashed format.
- Bulk UUID GeneratorGenerate many UUIDs at once — up to 1,000 UUID v4 or v7 values. Copy or download the list. Free and browser-based.
- The Nil UUID ExplainedThe Nil UUID is 00000000-0000-0000-0000-000000000000. See when to use it, how validators treat it, and why it is not a random ID.
- Uppercase GUID GeneratorGenerate an uppercase GUID / UUID. Some Windows APIs and .NET codebases expect hex A–F instead of a–f.
- UUIDs as Database Primary KeysShould you use UUID v4 or UUID v7 as a primary key? See how each version affects index locality, and generate sample keys.