Click Generate to create a UUID v7
UUID v7 Decoder
Bulk Generate
UUID v7 vs UUID v4
| Feature | UUID v7 | UUID v4 |
|---|---|---|
| Sortable | Time-ordered | Random order |
| Timestamp | 48-bit ms precision | None |
| Random bits | 74 bits | 122 bits |
| DB index performance | Excellent (sequential) | Poor (fragmented) |
| Standard | RFC 9562 | RFC 4122 |
| Format | 36 chars (8-4-4-4-12) | 36 chars (8-4-4-4-12) |
| Version nibble | 0111 (7) | 0100 (4) |
| Use case | DB keys, event streams | Opaque tokens, secrets |
Frequently Asked Questions
What is UUID v7?
UUID v7 is a time-ordered UUID format defined in RFC 9562. It embeds a 48-bit Unix timestamp (millisecond precision) in the most significant bits, followed by 74 bits of cryptographic randomness. This makes UUID v7s naturally sortable by creation time.
How is UUID v7 different from UUID v4?
UUID v4 is entirely random (122 random bits), making it unsortable and causing database index fragmentation. UUID v7 embeds a timestamp, so IDs sort chronologically. This dramatically improves B-tree index performance in databases like PostgreSQL and MySQL.
What is RFC 9562?
RFC 9562 is the IETF standard (published May 2024) that defines new UUID formats including v6, v7, and v8. It supersedes RFC 4122. UUID v7 is the recommended format for new applications needing time-ordered unique identifiers.
When should I use UUID v7 instead of UUID v4?
Use UUID v7 when you need database primary keys (better index locality), time-ordered event streams, distributed systems requiring sortable IDs, or any use case where chronological ordering matters. Stick with UUID v4 only when you need fully random, non-guessable IDs with no time information.
What are the database performance benefits of UUID v7?
UUID v7 dramatically reduces B-tree index fragmentation because new IDs are always appended near the end of the index. In PostgreSQL and MySQL benchmarks, UUID v7 primary keys show 2-10x better insert performance compared to UUID v4, with significantly smaller index sizes over time.
Is this tool free?
Yes, completely free. Everything runs in your browser using the Web Crypto API — no data is sent to any server.
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