ULID generator
Generate and decode ULIDs: 48-bit timestamp plus 80 bits of randomness.
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Tool guide
ULID generator: how it works
Practical information to understand the result and use this tool correctly.
About ULID generator
A ULID is 26 Crockford base32 characters: 10 for a millisecond timestamp and 16 for 80 bits of randomness. Lexical order matches creation time.
That is not UUID v4. UUID v4 is 36 hex characters with hyphens and is not time-sortable. This tool uses crypto.getRandomValues and does not upload the id.
Decode accepts lowercase and Crockford aliases I and L as 1, O as 0. U and any other symbol are rejected. Length must be 26 after spaces and hyphens are removed.
How to use it
- 1Generate one or more ULIDs, or paste one to decode.
- 2Read the UTC timestamp and the randomness block.
- 3Copy the id. Nothing leaves the browser.
Frequently asked questions
- What time is 01ARZ3NDEKTSV4RRFFQ69G5FAV?
- 2016-07-30T23:54:10.259Z. The first 10 characters encode 1469922850259 milliseconds.
- Is a ULID the same as a UUID?
- No. A ULID is 26 Crockford characters and sorts by time. UUID v4 is random hex and is not ordered by creation.
- Why is a trailing U rejected?
- Crockford base32 omits I, L, O, and U. I, L, and O are accepted as aliases on decode. U is not an alias.