ULID Generator
Generate ULIDs online: 128-bit, lexicographically sortable IDs with a 48-bit timestamp and 80 bits of randomness. Create up to 50 at once. Free and private.
What is the ULID Generator?
The ByteTools ULID Generator creates Universally Unique Lexicographically Sortable Identifiers — 26-character IDs that pack a 48-bit millisecond timestamp and 80 bits of randomness into Crockford's Base32.
- 128-bit ULIDs in Crockford Base32 (26 characters)
- 48-bit millisecond timestamp makes them sortable
- 80 bits of crypto-secure randomness
- Generate 1–50 at once
- Copy one or copy the entire batch
- 100% client-side — IDs never leave your browser
How to use the ULID Generator
- 1
Choose how many ULIDs you want (1–50).
- 2
Click Generate.
- 3
Each ULID embeds the current timestamp followed by secure randomness.
- 4
Copy a single ULID, or use Copy all to grab the whole batch.
About the ULID Generator
The ByteTools ULID Generator creates Universally Unique Lexicographically Sortable Identifiers — 26-character IDs that pack a 48-bit millisecond timestamp and 80 bits of randomness into Crockford's Base32. Because the timestamp comes first, ULIDs sort in creation order as plain strings, which makes them a friendlier alternative to UUIDs for database keys and logs.
The random portion is drawn from your browser's cryptographically secure random number generator, and the timestamp is read only when you click Generate, so IDs are unique and never computed during page render. You can create between 1 and 50 ULIDs at once and copy them all with a single click.
Generation runs 100% locally in your browser. Nothing is uploaded, logged or stored, so the IDs are yours alone and the tool works offline.
Frequently asked questions
What is a ULID?
A ULID is a 128-bit identifier encoded as 26 Crockford Base32 characters. The first 10 characters encode a 48-bit millisecond timestamp and the last 16 encode 80 bits of randomness, giving IDs that are both unique and sortable by creation time.
How is a ULID different from a UUID?
A UUID (v4) is fully random and unordered, so using it as a database key can hurt index locality. A ULID puts a timestamp first, so it sorts chronologically as a string, is a few characters shorter, and uses a case-insensitive, URL-safe alphabet.
Are ULIDs sortable?
Yes. Because the timestamp occupies the high-order bits and Crockford Base32 preserves order, sorting ULIDs as text also sorts them by the time they were created. IDs made in the same millisecond are ordered by their random component.
Are these ULIDs cryptographically random?
The 80-bit random portion is generated with crypto.getRandomValues, the browser's cryptographically secure random source, so the chance of a collision within the same millisecond is astronomically small.
Are the ULIDs generated on a server?
No. Every ULID is created locally in your browser with JavaScript, using the current time and secure randomness. Nothing is uploaded, logged or stored, so the tool works offline and keeps your IDs private.
Guides for ULID Generator
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