ULID Generator

About the ULID Generator

A ULID is a 26-character identifier encoding a millisecond timestamp followed by random data, using Crockford's Base32 so it is case-insensitive and URL-safe. Because the timestamp comes first, ULIDs generated over time sort lexicographically in creation order, which is friendly to database indexes and log sorting, unlike random UUIDs. This tool generates them with the browser's secure random source.

The layout is fixed. The first 10 characters hold the milliseconds since the Unix epoch and the remaining 16 carry 80 bits of randomness. Crockford's alphabet drops the letters I, L, O and U, so a value read aloud or retyped from a screenshot is hard to garble. The gotcha is ordering inside a single millisecond: the specification allows a monotonic counter, but plain random ULIDs minted in the same millisecond can come back in any order, so do not lean on them to break ties in a tight insert loop.

ULIDs are more compact than UUIDs (26 characters versus 36) and avoid the special characters that can cause trouble in URLs, which makes them a reasonable public-facing key for orders, invoices and event records. Remember that the leading timestamp is readable by anyone holding the identifier, so a ULID in a URL quietly discloses when the row was created; use a random identifier instead if that matters. UUID version 7 offers similar time-ordering in the standard UUID format; see the UUID Generator. To turn a ULID's timestamp back into a date, decode the leading section and paste the milliseconds into the Unix Timestamp Converter.

How to use

1. Choose how many to generate.
2. Copy or download the ULIDs.
3. They sort in creation order as text.