UUID Generator — Bulk v4 & v7
Generate RFC 9562-compliant UUID version 4 (random) or version 7 (time-ordered, sortable) in batches of 1 to 100. Toggle uppercase and hyphens. Everything runs in your browser — nothing is ever sent anywhere.
All UUIDs are generated entirely inside your browser. Nothing is sent to any server.
Generated UUIDs
Press "Generate" to see UUIDs here.
How to use
- Choose a version (v4 or v7) and how many UUIDs to generate (1–100).
- Optionally toggle uppercase and no-hyphens formatting.
- Press "Generate" to get a list of UUIDs, then copy them individually or all at once.
How it works
UUIDv4 (random)
Of the 128 bits, 4 bits encode the version and 2 bits encode the RFC 4122 variant; the remaining 122 bits are filled with cryptographically secure random data from crypto.getRandomValues(). In the hex representation, the 15th character is always 4 and the 20th character is always one of 8, 9, a, or b.
UUIDv7 (time-ordered)
The first 48 bits hold the current Unix timestamp in milliseconds, followed by a 4-bit version, 12 bits of random data, a 2-bit variant, and 62 more bits of random data (per RFC 9562). Because the timestamp comes first, sorting generated UUIDs as strings reproduces their generation order (chronological order). Ordering among UUIDs generated within the same millisecond is not guaranteed — RFC 9562 does not require it.
About the randomness source
All random bytes come from the Web Crypto API's crypto.getRandomValues(). Math.random() is not used, since it can be predictable and is unsuitable for cryptographic purposes.
Formatting options
Uppercase and hyphen toggles only affect display formatting — the underlying UUID value is unchanged.
FAQ
Should I use UUIDv4 or UUIDv7?
Use v4 if you just need pure randomness. Use v7 if you want IDs that sort chronologically, such as database primary keys — its leading timestamp gives better index locality.
Can generated UUIDs collide with each other?
In theory it's not impossible, but v4 has 122 bits of randomness and v7 has 74 bits, so collisions are not a practical concern.
Is my input or the generated output sent to a server?
No. UUID generation happens entirely inside your browser, and no data is transmitted anywhere.
Do you support UUIDv1, v3, or v5?
No. v1 depends on device information like MAC addresses, and v3/v5 are for hashing a namespace plus a name string — both are far less commonly needed than v4 and v7, so this tool only covers v4 and v7.
Is there a limit on how many UUIDs I can generate at once?
You can generate between 1 and 100 at a time. Any value above 100 is automatically clamped down to 100.
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