UUID/GUID Generator

UUID Version Selection
Generated UUIDs
UUID Decoder & Validator
UUID Version Info
Version 4 - Random

Randomly generated UUID with 122 bits of randomness. Most commonly used version for general purposes.

UUID Structure

Standard UUID format:

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
  • M: Version digit (1-7)
  • N: Variant bits (8, 9, A, or B)
  • Total: 128 bits / 32 hex digits
Common Use Cases
  • 🗄️ Database Primary Keys
  • 📡 API Resource IDs
  • 🔗 Unique Identifiers
  • 📊 Distributed Systems
  • 🔄 Message IDs
Quick Actions

UUID v7 - Time-Sortable UUIDs

UUID v7 leads with a 48-bit Unix millisecond timestamp, so IDs sort by creation time and append cleanly to B-tree indexes - the modern default for database keys.

How this version compares with the other six - and when each one earns its keep - is covered in UUID versions explained.

When to Use This Version

Use UUID v7 for database primary keys where time-ordering improves index performance, event sourcing, audit logs, distributed tracing, and any scenario combining uniqueness with chronological sorting. V7 is the modern replacement for v1 and v6.

Best Practices

V7 is excellent for B-tree indexes - new IDs append rather than scatter. The 48-bit timestamp supports dates through year 10889. Sub-millisecond ordering uses random bits, so IDs within the same millisecond aren't guaranteed sequential. Compare with ULID if you need Base32 encoding (26 chars vs 36).

Compare with Other Versions

v4 Random
GUID
View All UUID Versions

Related Tools

UUID/GUID Generator ULID Generator ObjectID Generator Unix Timestamp

UUID Version 7 Questions

UUID v7 uses a 48-bit Unix millisecond timestamp followed by random bits. It's time-sortable, privacy-friendly (no MAC address), and the recommended choice for new applications needing time-ordered IDs.

Best of both worlds: time-sortable like v1/v6, but with Unix timestamps (widely understood) and no machine identification (privacy). Plus 74 bits of randomness for uniqueness within the same millisecond.

Similar concepts - both are time-sortable 128-bit IDs. V7 is the official UUID standard, uses hex encoding (36 chars). ULID uses Crockford Base32 (26 chars), slightly more compact. Choose based on ecosystem compatibility.

Milliseconds. The 48-bit timestamp supports dates from 1970 to year 10889. Sub-millisecond ordering uses random bits - not guaranteed sequential within the same millisecond.