How do I generate a UUID or GUID?
Open FixDoks's UUID Generator, choose version 4 for a fully random ID or version 7 for one that sorts by creation time, enter how many you need, and click Generate. Create up to 10,000 at once in formats like uppercase, no hyphens or braces, and paste any UUID back in to validate or decode it.
UUID Generator at a glance
| Versions | v4 random or v7 time-ordered |
|---|---|
| Batch limit | Up to 10,000 UUIDs at once |
| Processing | In your browser; your files are not uploaded |
| Price | Free |
| Works on | Chrome, Edge, Safari and Firefox on Windows, Mac, Android and iPhone |
How to use UUID Generator
- Choose Version 4 (random) or Version 7 (time-ordered).
- Enter how many you need, up to 10,000.
- Pick a format: uppercase, no hyphens, braces or quoted for code.
- Click Generate UUIDs, then copy or download them. Paste any UUID in the checker to validate or decode it.
What is a UUID?
A UUID (universally unique identifier), called a GUID in the Microsoft world, is a 128-bit number written as 32 hexadecimal characters in five groups, for example 3f2b8c1e-9a4d-4c7b-b2e1-5d8f0a6c9e21. Systems use UUIDs as IDs for database rows, files, orders, API requests and devices, because anyone can create one without asking a central server and the chance of two being the same is negligible.
Version 4 or version 7?
| UUID v4 | UUID v7 | |
|---|---|---|
| Contents | 122 random bits | 48-bit Unix time in milliseconds + 74 random bits |
| Sort order | Random | Sorts by creation time |
| Best for | General IDs, tokens that reveal nothing | Database primary keys, logs, event streams |
| Reveals | Nothing | When it was created |
Version 4 is the classic random UUID and works everywhere. Version 7, standardised in RFC 9562 in 2024, puts a timestamp at the front, so new IDs always sort after older ones. Databases store sorted keys much more efficiently, so v7 is becoming the preferred choice for primary keys in PostgreSQL, MySQL and similar systems. UUIDs generated here in the same millisecond still come out in increasing order. Do not use v7 where the creation time should stay private.
How unique are they?
A v4 UUID has 122 random bits, about 5.3 × 1036 possibilities. You would need to generate around 2.7 quintillion UUIDs before the chance of even one duplicate reached 50 percent. The generator uses your browser's cryptographic random source, which is essential: IDs made with weak random functions are far more likely to clash.
Formats
- UPPERCASE: some Windows and .NET tools display GUIDs in capitals. Case does not change the value.
- No hyphens: 32 characters, used in some URLs and file names.
- Braces: the {GUID} style used in the Windows registry and some C# code.
- Quote and comma: ready to paste into an SQL IN (...) list or a code array.
Validate and decode
Paste any UUID in the checker to see if it is valid, which version it is, and which variant. For v7 and v1 UUIDs it also shows the embedded creation time in UTC, which is handy when debugging logs. The special nil UUID (all zeros) and max UUID (all f) are recognised too.
Generating UUIDs in code
Modern browsers and Node.js have crypto.randomUUID() for v4. Python has uuid.uuid4(), and PostgreSQL has gen_random_uuid(). Support for v7 is newer, so check your language or database version, or generate v7 values here for test data and fixtures.