Micro Tools
Advertisement

UUID v1 Generator

Generate time-based UUIDs (version 1) right in your browser. Each ID embeds a 60-bit timestamp with 100-nanosecond precision plus random clock and node fields, so IDs created later sort after earlier ones.

UUID v1 options

Time-based IDs that sort roughly by creation time.

Press Generate UUIDs.

Everything runs locally. Nothing is sent to any server.

Advertisement

How UUID v1 works

A version 1 UUID packs three things into 128 bits: a 60-bit count of 100-nanosecond intervals since 15 October 1582, a 14-bit clock sequence that guards against clock rollbacks, and a 48-bit node identifier. The version nibble is set to 1 and the variant bits mark it as RFC 4122. This tool builds the timestamp from your system clock and fills the clock and node fields with cryptographic randomness.

When to use version 1

Use v1 when you want IDs that are roughly time-ordered, which keeps database indexes and log files naturally sorted by creation time without a separate timestamp column. It is a classic choice for event sourcing, audit logs and distributed systems. If you need IDs that reveal nothing about when or where they were made, UUID v4 or v7 is the better fit.

Related tools

JSON formatterFormat and validate JSON, privately. Regex testerTest regex live with highlighting. Base64 encoderBase64 encode and decode, plus URL encoder and JWT decoder.

UUID v1 Generator FAQs

Are UUID v1 values unique?
Practically yes. The 60-bit timestamp plus 14 random clock bits plus 48 random node bits give about 122 bits of entropy per millisecond, so collisions are effectively impossible in real use.
Do UUID v1 values sort by time?
Roughly. The most significant bits hold the timestamp, so IDs generated later sort after earlier ones when compared as strings. IDs made within the same 100-nanosecond tick differ only in the random clock and node fields.
What is the 1582 date in the timestamp?
UUID time counts 100-nanosecond intervals since 15 October 1582, the date of the Gregorian calendar reform. It is the epoch defined by the UUID specification, not a bug.
Does generating UUIDs here expose my MAC address?
No. Classic v1 used the machine MAC as the node field, but this tool uses a random 48-bit node instead, so nothing about your device leaks into the ID.
UUID v1 vs v4 vs v7, which should I pick?
Pick v1 for time-ordered IDs in legacy systems, v4 when you want pure randomness with no time information, and v7 for modern time-ordered IDs with better database index locality.
Advertisement