UUID Generator
Generate random UUIDs (also called GUIDs) one at a time or up to 1,000 at once. Pick version 4, 7, 1, or 5, choose the format, and copy or download the list. Everything runs in your browser.
What is a UUID?
A UUID (universally unique identifier) is a 128-bit ID that can be created anywhere, by anyone, without checking a central list, and still be unique in practice. It is written as 32 HEX digits in five groups, like this:
886313e1-3b8a-5372-9b90-0c9aee199e5d
The first digit of the third group is the version (here 5). The first digit of the fourth group is the variant, which is 8, 9, a, or b for standard UUIDs. The rules are set by RFC 9562, which replaced the older RFC 4122 in 2024.
Why use our UUID generator
- ·Free. No signup, no paywall, no limits.
- ·Four versions. Random v4, time-ordered v7, v1, and name-based v5 in one place.
- ·Bulk generation. Up to 1,000 UUIDs at once, with copy all and .txt download.
- ·Any format. Uppercase GUIDs in braces, no hyphens, quotes, or urn:uuid:.
- ·Private. Made with your browser's secure random number generator. Nothing is uploaded.
How to generate a UUID
- 1
Pick a UUID version
Version 4 (random) is the default and works for most jobs. Choose version 7 for database keys that should sort by time, version 1 for older systems that expect it, or version 5 to turn a name into a fixed UUID.
- 2
Set how many you need
Enter any number from 1 to 1,000. A fresh batch appears as soon as you change the number, and the Generate button makes a new one at any time.
- 3
Choose the format
Turn on Uppercase or turn off Hyphens if your system needs it, and wrap each UUID in braces, quotes, or a urn:uuid: prefix. The list updates without changing the UUIDs themselves.
- 4
Copy or download
Copy a single UUID with the button next to it, copy the whole list at once, or download it as a .txt file with one UUID per line.
UUID versions compared: v4 vs v7 vs v1 vs v5
Every version produces the same 36-character format. What changes is how the bits are filled in, and that decides where each one fits best.
| Version | Built from | Best for |
|---|---|---|
| Version 4 | 122 random bits | General IDs, API keys, test data. The safe default. |
| Version 7 | Unix time in milliseconds, then random bits | Database primary keys. New rows sort in the order they were made. |
| Version 1 | Time in 100 ns steps, clock sequence, node ID | Older systems and libraries that require it. |
| Version 5 | SHA-1 hash of a namespace and a name | A fixed ID for a known name, like a domain or URL. |
If you are choosing a key for a new database table, version 7 is usually the better pick over version 4. Random v4 keys land all over a database index, while v7 keys are added at the end in time order, so inserts stay fast as the table grows. The tradeoff is that a v7 UUID shows when it was created, down to the millisecond.
UUID formats: GUIDs, braces, and no hyphens
Different systems write the same UUID in slightly different ways. They all hold the same value, so pick the one your code or tool expects:
- ·Standard:
886313e1-3b8a-5372-9b90-0c9aee199e5d - ·Microsoft GUID:
{886313E1-3B8A-5372-9B90-0C9AEE199E5D} - ·No hyphens:
886313e13b8a53729b900c9aee199e5d - ·URN:
urn:uuid:886313e1-3b8a-5372-9b90-0c9aee199e5d
Uppercase and lowercase mean the same thing, but the standard asks for lowercase output, so use lowercase unless a system needs otherwise.
When to use a UUID
- ·Database primary keys. UUIDs let different servers or offline apps create rows without asking a central database for the next number. Version 7 keeps new rows in time order, which is easier on database indexes than fully random keys.
- ·API request and idempotency keys. Attach a unique ID to each request so a server can spot retries and avoid charging or creating something twice.
- ·Test data and fixtures. Generate a batch of IDs to paste into seed files, mock JSON, or spreadsheets.
- ·File and object names. Name uploads, temporary files, or storage objects with a UUID so two names never clash.
- ·Stable IDs from names. Use version 5 when the same input, such as a URL or an email address, must always map to the same UUID across systems.
Frequently asked questions
- How do I generate a UUID?
- Open this page and a random version 4 UUID is already there. Click the copy button to copy it, or click Generate UUID for a new one. To make more at once, set How many to any number up to 1,000.
- Which UUID version should I use?
- Use version 4 if you just need a unique ID. Use version 7 for database primary keys, because the IDs sort by creation time. Use version 5 when you need the same UUID every time for the same name. Version 1 is mostly for older systems that expect it.
- Can two UUIDs ever be the same?
- In practice, no. A version 4 UUID has 122 random bits, so you would need to generate about 2.71 quintillion of them for a 50% chance of a single duplicate. This tool uses your browser's secure random number generator, the same one used for encryption keys.
- What is the difference between a UUID and a GUID?
- They are the same thing. GUID (globally unique identifier) is the name Microsoft uses, and GUIDs are often written in uppercase inside braces, like {886313E1-3B8A-5372-9B90-0C9AEE199E5D}. Turn on Uppercase and choose Braces to get that format.
- How can I tell which version a UUID is?
- Look at the first character of the third group. In 886313e1-3b8a-5372-9b90-0c9aee199e5d it is 5, so this is a version 5 UUID. You can also paste any UUID into Check a UUID on this page to see its version, variant, and, for versions 1, 6, and 7, when it was created.
- Does a version 1 UUID from this page contain my MAC address?
- No. Browsers cannot read your network card's MAC address, so the node part of each version 1 UUID is random, with the multicast bit set as the UUID standard asks for in that case. The timestamp is still your device's real clock time.
- Why does version 5 always give me the same UUID?
- That is how it is designed. A version 5 UUID is a hash of the namespace and the name, so the same pair always produces the same UUID, on any computer. Change the name or the namespace to get a different one. Names are case-sensitive, so Example.com and example.com give different UUIDs.
- Are UUIDs safe to use as secrets or passwords?
- No. A UUID is built to be unique, not secret. Version 1 and 7 UUIDs reveal when they were made, and version 5 UUIDs can be recreated by anyone who knows the name. Use the random password generator for passwords and secret keys.
- Are the UUIDs sent or saved anywhere?
- No. They are generated in your browser and nothing is uploaded or stored. When you close or reload the page, they are gone.