ULID Generator

Generate time-ordered, URL-safe ULIDs in bulk — sortable by creation time, copy-ready in one click. Decode any ULID to its timestamp below.

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What is a ULID?

A ULID (Universally Unique Lexicographically Sortable Identifier) packs two things into 26 URL-safe characters: a 48-bit millisecond timestamp (the first 10 characters, Crockford Base32) and 80 bits of cryptographic randomness (the remaining 16). Because the timestamp leads, ULIDs generated later always sort after earlier ones — no separate created_at column needed for ordering.

ULID vs UUID

UUID v4 is purely random and doesn't sort. UUID v7 is time-ordered like a ULID but keeps the 36-character hyphenated format. ULID is shorter (26 chars), case-insensitive, URL-safe with no special characters, and excludes easily confused characters (I, L, O, U). Pick ULIDs for human-friendly sortable IDs in logs, filenames, and database keys.

FAQ

What is a ULID?
A ULID (Universally Unique Lexicographically Sortable Identifier) is a 26-character, URL-safe ID: a 48-bit millisecond timestamp in Crockford Base32 followed by 80 bits of randomness. Because the timestamp comes first, ULIDs sort in creation order.
ULID vs UUID — which should I use?
Use ULIDs when you want IDs that sort by creation time without a separate timestamp column — great for database primary keys and logs. Use UUID v4 for purely random IDs, or UUID v7 if you need a standards-track (RFC 9562) time-ordered UUID.
Can you recover the timestamp from a ULID?
Yes. The first 10 characters encode the Unix timestamp in milliseconds — paste any ULID into the decoder above to see it. Keep in mind this means a ULID reveals roughly when it was created.
Is it safe to generate ULIDs in the browser?
Yes. The random part comes from crypto.getRandomValues, a cryptographically secure source, and everything runs locally — your IDs are never uploaded or stored.
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