UUID Generator

Generate RFC-compliant UUIDs (v1, v4, v7). Choose version, count, and format — then copy with one click.

All UUIDs are generated locally in your browser using the Web Crypto API. Nothing is sent to any server.

UUID Versions

UUID v4 uses cryptographically random bytes — the most common choice. UUID v1 encodes the current timestamp and a pseudo-random node, making it partially sortable. UUID v7 (RFC 9562) combines a Unix millisecond timestamp with random bits for both sortability and uniqueness.

Output Formats

The standard format is 8-4-4-4-12 hex with lowercase letters. You can also choose UPPERCASE, {braces} (common in Windows APIs), urn:uuid: (RFC 4122 URN namespace), or no-dash (compact 32-character hex).

FAQ

Is UUID v4 truly unique?

UUID v4 has 122 random bits, giving about 5.3 × 10³⁶ possible values. Collisions are astronomically unlikely for any practical workload.

When should I use v7 instead of v4?

Use v7 when you need database-friendly, time-sortable IDs. The embedded millisecond timestamp lets B-tree indexes stay sequential, reducing page splits.

Related tools

Base64 / URL Encode·Decode · JSON Formatter · Unix Timestamp Converter