Question 1

How does UUIDv7 generation work?

Accepted Answer

UUIDv7 embeds a Unix timestamp in milliseconds in the first 48 bits (12 hex characters), followed by a version nibble (7), then random or pseudo-random data for uniqueness. This makes UUIDv7s naturally sortable by creation time while maintaining global uniqueness.

Question 2

Can I generate a UUIDv7 from a custom timestamp?

Accepted Answer

Yes. This tool lets you enter a specific Unix timestamp in milliseconds or pick a date/time using the date picker. The timestamp is embedded in the first 48 bits, while the remaining bits are filled with random data to ensure uniqueness.

Question 3

Are UUIDv7s generated in the browser truly unique?

Accepted Answer

UUIDv7 combines a millisecond-precision timestamp with 74 bits of randomness from Math.random(). While this provides very high uniqueness for client-side demos and prototyping, production systems should use a cryptographically secure random number generator (e.g., crypto.getRandomValues) for the random portion.

Question 4

How many UUIDv7s can I generate at once?

Accepted Answer

This tool supports bulk generation of 1, 5, 10, 25, or 50 UUIDv7s at a time. All share the same timestamp (current time or your custom value) but have different random bits, so each is unique.

Question 5

What is the difference between UUIDv7 and UUIDv4?

Accepted Answer

UUIDv4 is entirely random (122 random bits), while UUIDv7 uses the first 48 bits for a timestamp and the remaining bits for randomness. This makes UUIDv7 time-sortable and better suited for database primary keys, as it preserves insertion order and improves B-tree index performance.

UUIDv7 Generator

Generation Options

Generated UUIDs

How UUIDv7 Generation Works

Unix Timestamp

Version (7)

Random Data

Frequently Asked Questions

Related Tools & Articles