ULID Generator

About this tool

What Is ULID Generator? The ULID Generator creates Universally Unique Lexicographically Sortable Identifiers. Each 26-character Crockford Base32 ID embeds a 48-bit millisecond timestamp (the first 10 characters) plus 80 bits of random entropy, so ULIDs carry their creation time and sort chronologically without a database sequence. How It Works A ULID is built from a millisecond timestamp (first 10 characters) and randomness (remaining 16) using Crockford Base32. The tool also supports monotonic generation for high-throughput creation within the same millisecond, so identifiers remain strictly increasing. Worked Example The generated ULID 01J8XK2ZXN4KQW8D5PTQ0N1R3Y decodes to a timestamp prefix (01J8XK2ZXN4) that maps to a UTC millisecond time, while the remaining 16 characters are random. Sorting by string order equals sorting by creation time. Common Use Cases order-preserving primary keys in distributed stores request and event correlation IDs with creation time database keys where chronological sort matters Important Notes the timestamp is UTC milliseconds, not local time ULID randomness is not cryptographically secure — use UUID v4 or a CSPRNG for secrets or tokens 26 characters is shorter than UUID's 36, so ULIDs save space in keys and URLs Related Tools UUID Generator — generate random UUID (v4) identifiers. Slug Generator — make clean URL slugs from text. API Key Generat