Generate UUIDs (v4 or v7)
Generate 1 to 100 random UUID v4 or time-ordered UUID v7 identifiers with crypto-grade randomness.
A UUID is a 128-bit identifier written as 32 hexadecimal digits in five groups: 8-4-4-4-12. Version 4 fills 122 of those bits with random data, so the chance of two colliding is negligible even across billions of records. Version 7 (RFC 9562, 2024) puts a 48-bit millisecond timestamp first and random bits after, so ids sort by creation time, which keeps database indexes compact and makes "newest first" queries cheap.
Randomness comes from crypto.getRandomValues, the same cryptographically secure source browsers use for TLS, never from Math.random. Generation happens on your device; the ids are not drawn from a shared pool and no server sees them.
Use uppercase if a system such as Microsoft SQL Server or a Windows registry entry displays GUIDs that way; the value is identical. Drop the hyphens for systems that store the 32 hex characters raw.
How to use it
- Choose v4 for general-purpose ids or v7 when ids will be primary keys that should sort by time.
- Set how many you need (1 to 100).
- Optionally switch to uppercase or remove hyphens.
- Click Generate, then copy the list or download it as a text file. Click again for a fresh batch.
Frequently asked questions
What is the difference between a UUID and a GUID?
None in practice. GUID is Microsoft's name for the same 128-bit format. Windows tools tend to show them in uppercase and sometimes in braces; the bits are the same.
Should I use v4 or v7 for a database primary key?
v7. Random v4 keys insert at random positions in a B-tree index, causing page splits and cache misses at scale. v7 keys are monotonic within a millisecond, so inserts are appended. If exposing creation time in the id is a concern, use v4.
Are these UUIDs unique?
Statistically, yes: with 122 random bits you would need to generate about 2.7 quintillion v4 UUIDs before a 50% chance of one collision. They are not registered anywhere, so nothing checks them centrally, and nothing needs to.
Can I generate a UUID from a name (v5)?
Not with this tool. v3 and v5 hash a namespace plus a name and always give the same result for the same input; they are for deterministic ids, a different use case.
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