UUID Generator
Generate random v4 or time-ordered v7 UUIDs in bulk.
Options
Generated UUIDs
How to generate UUIDs
Pick Version (v4 random or v7 time-ordered), set the Quantity up to
1000, and toggle Uppercase or Hyphens to match the format your
system expects. IDs generate automatically and refresh whenever an option changes — press
Generate again for a fresh batch. Copy the list or download it as
uuids.txt, one ID per line. Everything runs in your browser, so generated IDs are
never uploaded or stored.
UUID v4 vs v7
| Aspect | v4 | v7 |
|---|---|---|
| Source of uniqueness | v4 Random | v7 Time-ordered |
| Randomness | 122 random bits | ~74 random bits + timestamp |
| Ordering | No order, random sort position | Sortable by creation time |
| Database indexes | Random inserts can fragment B-tree indexes | Monotonic inserts stay index-friendly |
| Opacity | Opaque, leaks nothing | Embeds creation time in milliseconds |
Format
Every UUID is 128 bits, written as 32 hexadecimal characters in five groups:
xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
M is the version digit (4 or 7) and N is the
variant nibble, one of 8, 9, a or b. Turning
off hyphens gives the compact 32-character form; uppercase gives the same digits in
A–F.
Examples
ID values are random, so the shapes below show the pattern each setting produces — your generated IDs will differ but follow the same shape.
| Settings | Shape (pattern, not a real ID) |
|---|---|
| v4, lowercase, hyphens | ________-____-4___-____-____________ (pattern: version digit is 4) |
| v7, lowercase, hyphens | ________-____-7___-____-____________ (pattern: version digit is 7) |
| v4, uppercase, no hyphens | ________________________________ (pattern: 32 hex chars, no dashes) |
Limits and edge cases
- Uniqueness is probabilistic: a v4 ID has 122 random bits, so collisions happen with probability around 2-122 per pair — negligible, but keep a unique constraint in your database.
- v7 IDs embed the creation timestamp in milliseconds, so they reveal when they were made. Use v4 when the ID must be fully opaque.
- v7 ordering depends on the device clock: if the clock jumps backwards, newer IDs can sort before older ones.
- Quantity is capped at 1000 IDs per batch; generate again for more.
Frequently asked questions
What is the difference between UUID v4 and v7?
Version 4 IDs are fully random (122 random bits), so they carry no ordering or time information. Version 7 IDs start with a millisecond timestamp followed by random bits, so IDs created later sort after earlier ones, which keeps database indexes fast.
What is a GUID? Is it the same as a UUID?
GUID (globally unique identifier) is Microsoft's name for the same 128-bit format. A v4 GUID and a v4 UUID are interchangeable; both follow the same layout with a version nibble and variant bits.
Are generated UUIDs guaranteed to be unique?
Effectively yes, but not by construction. A v4 UUID has 122 random bits, so the chance of a collision is about 1 in 2^122, far smaller than any realistic batch. If you need uniqueness in a database, still enforce it with a unique constraint.
Does UUID v7 leak my timestamp or identity?
A v7 ID embeds the creation time in milliseconds, so anyone reading it can tell when it was made. That is usually harmless, but do not use v7 where the creation time itself is sensitive. Use v4 for fully opaque identifiers.
Can I generate UUIDs in bulk?
Yes. Set the quantity up to 1000 and the tool generates the whole batch at once, one ID per line. Copy the list or download it as a .txt file.
Are my UUIDs uploaded anywhere?
No. Generation runs in your browser with the platform random number generator and nothing is sent to a server. Generated IDs are never saved; only your display options are remembered in your browser's local storage.