UUID v4 vs v7: Which One Should You Use in 2025?

Published April 2025 · 5 min read

UUID v4 has been the default for years, but UUID v7 is gaining traction. Here's when to use each.

UUID v4 (Random)

550e8400-e29b-41d4-a716-446655440000

Completely random. No ordering. No timestamp. Simple and widely supported.

UUID v7 (Time-Sorted)

018f0ecb-a845-7000-8000-000000000000

Embeds a Unix timestamp in the first 48 bits. UUIDs sort chronologically.

When to Use v4

  • You don't need time-ordering
  • Maximum randomness is important
  • Backward compatibility with existing systems

When to Use v7

  • Database primary keys (much better index performance)
  • You need to sort by creation time
  • Distributed systems where time-ordering helps
  • New projects starting in 2025

Database Performance

v7 is significantly better for database indexes because sequential IDs cause less B-tree fragmentation than random v4 UUIDs. If you're using UUIDs as primary keys, v7 is the clear winner.

Generate UUIDs

Use our UUID Generator to create v4 UUIDs instantly.

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