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UUID v1 generator (time-based)

The UUID v1 generator draws an identifier whose first fields encode its creation moment: a 60-bit timestamp of 100-nanosecond ticks since 1582-10-15, a fixed version nibble of 1, a 14-bit clock sequence, and a 48-bit node id in the standard 8-4-4-4-12 layout. The node id is random per session, so consecutive values from one open page share their last 12 characters and differ in the leading time fields. Teams reach for v1 when keys should sort roughly by creation time.

Open UUID v1 Generator in the app Browse all tools

How to use UUID v1 Generator

  1. Open UUID v1 Generator in the Toolbox101 app; one time-based UUID is already in the Output box.
  2. Click Generate New for another value: the timestamp fields advance while the trailing node id stays the same for this session.
  3. Click Copy to take the identifier, or read it straight from the Output box.

Worked example

UUID v1 Generator gives a different result every time, so yours will differ. This is one run:

Output

4db2a9c0-bd94-11f1-a63d-41b8aa7a9ee9

Frequently asked questions

When should I pick UUID v1 over UUID v4?

Choose v1 when creation order matters (migration keys, event logs, or a schema where roughly time-ordered values help) because its timestamp prefix advances with the clock. Choose v4 when values must be unpredictable or reveal no timing, since v4 is built from 122 random bits.

Does a v1 UUID reveal the machine that created it?

Not through this tool. RFC 4122 allows a node field of six random bytes with the multicast bit set, which is what this generator uses instead of a MAC address, so the value identifies a session, not hardware. The timestamp part is still readable: the first fields encode the creation moment in 100-nanosecond ticks.

Why do consecutive values share the same last 12 characters?

The last 12 hex characters are the 48-bit node id, drawn once per session and reused, so within one open page every value ends the same way. The clock sequence, two characters before it, only changes when two calls land in the same tick or the clock moves backwards.

What fields make up a UUID v1?

Reading left to right: time_low (32 bits), time_mid (16 bits), time_hi_and_version (16 bits with the version nibble set to 1), clock_seq_hi_and_reserved plus clock_seq_low (16 bits with the variant bits set), and node (48 bits). Together they describe when the UUID was created and by which node.

Use UUID v1 Generator now

Open UUID v1 Generator in the app

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