Skip to content
UL

ULID Generator

Generate ULIDs and decode their timestamps.

48-bit millisecond timestamp + 80-bit randomness (crypto.getRandomValues). Same-ms ids stay lexicographically sortable when monotonic.

About ULID Generator

ULIDs are 128-bit identifiers encoded as 26 Crockford Base32 characters: a 48-bit Unix millisecond timestamp plus 80 bits of randomness. Unlike UUIDs, they sort lexicographically by creation time—handy for database keys and correlation IDs. toco.tools bulk-generates ULIDs with optional monotonic increments within the same millisecond. Randomness comes only from crypto.getRandomValues (never Math.random). Paste an existing ULID to recover its embedded timestamp (ms, UTC, local) and randomness suffix. Case and hyphens are accepted. Everything runs locally in your browser.

How to use

  1. Set count and options
  2. Copy results (or switch to Decode)
  3. Paste a ULID to inspect its timestamp

FAQ

How does ULID differ from UUID?

ULIDs embed a creation timestamp so they sort lexicographically by time. UUID v4 is fully random; UUID v7 also carries time.

What is monotonic mode?

When several ULIDs share a millisecond, the random part increments so they stay lexicographically ordered (spec monotonicity).

Are ULIDs sent to a server?

No. Generation and timestamp decoding run entirely in your browser.