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

Free Online UUID v1 Generator - Time-based Identifier Tool

Generate UUID v1 online for free. This browser-based tool creates time-based UUIDs combining a 60-bit timestamp, clock sequence, and MAC address - no installation or registration required.

When to Use This Version

Use UUID v1 when you need to extract creation timestamps from IDs, require chronological ordering for audit logs or event sourcing, or want to debug with visible time information. Avoid v1 if privacy is a concern - the MAC address is embedded and can identify the generating machine.

Best Practices

For new projects needing time-based UUIDs, consider v7 instead (better privacy, simpler timestamps). If you must use v1, understand that IDs don't sort lexicographically by time - use v6 for that. Never use v1 as a security token - the clock sequence can be predicted.

Compare with Other Versions

v4 Random
v7 Unix Time
v5 Name-based
GUID
View All UUID Versions

Related Tools

UUID/GUID Generator ULID Generator ObjectID Generator Unix Timestamp

UUID Version 1 Questions

UUID v1 is a time-based identifier that combines a 60-bit timestamp (100-nanosecond intervals since 1582), a 14-bit clock sequence, and a 48-bit node ID (typically MAC address). This ensures uniqueness across time and machines.

Use v1 when you need chronological ordering and can extract creation time from the ID. Good for audit logs, event sourcing, or when debugging needs timestamp visibility. Avoid if privacy is a concern - MAC address is embedded.

The MAC address embedded in v1 reveals machine identity. Clock sequence leaks generation count. If privacy matters, use v4 (random) or v7 (timestamp without machine info).

Not by default string sorting - the timestamp bits are scattered. Use v6 or v7 if you need lexicographic time-sorting. V1 still embeds time, you just need special handling to extract and sort by it.