UUID Generator - v1, v4, v7, NIL & GUID

Free online UUID / GUID generator for v1, v4, v7, and NIL UUIDs. Bulk generate, validate, parse timestamps and variants. RFC 4122 / 9562 compliant. 100% client-side.

Features

• Generate v1 (time), v4 (random), v7 (time-sortable), and NIL UUIDs
• Bulk generation (up to thousands at once)
• Validate and parse existing UUIDs
• Extract timestamp from v1 / v7 UUIDs
• Formatting options (uppercase, braces, hyphenless)
• Cryptographically secure randomness (CSPRNG)
• 100% client-side

Frequently Asked Questions

What is the difference between UUID versions?

v1 is time-based (uses the machine clock and MAC address), v4 is fully random, and v7 is time-ordered with random bits, ideal for database primary keys because it sorts chronologically while remaining unique. NIL (all zeros) is a special placeholder UUID.

Can two generated UUIDs collide?

Practically no. A v4 UUID has 122 bits of randomness, giving ~5.3×10^36 possible values. The chance of a collision among 103 trillion randomly generated v4 UUIDs is still about one in a billion. v7 collision risk is even lower thanks to the timestamp component.

Which UUID version should I use for a database primary key?

Use v7. It is time-ordered, so rows insert in chronological order (good for B-tree index locality) and remain sortable by creation time. v4 is fine when order does not matter; avoid v1 if exposing the machine MAC address is a concern.