Click Generate to create a ULID
ULID Decoder
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ULID vs UUID Comparison
| Feature | ULID | UUID v4 |
|---|---|---|
| Length | 26 chars | 36 chars |
| Encoding | Crockford Base32 | Hexadecimal |
| Sortable | ✓ Yes | ✗ No |
| Timestamp | ✓ 48-bit ms | ✗ None |
| URL-safe | ✓ Yes | ✗ Hyphens |
| Case-insensitive | ✓ Yes | ✓ Yes |
Frequently Asked Questions
What is a ULID?
ULID stands for Universally Unique Lexicographically Sortable Identifier. It's a 128-bit identifier that encodes a timestamp in the first 48 bits and 80 bits of randomness. ULIDs are represented as 26-character Crockford Base32 strings.
How is ULID different from UUID?
ULIDs are lexicographically sortable (they sort by creation time), more compact (26 chars vs 36), URL-safe (no hyphens or special chars), and encode a millisecond-precision timestamp. UUIDs v4 are random and unsortable; UUID v7 is sortable but longer.
When should I use ULID instead of UUID?
Use ULIDs when you need sortable IDs for database primary keys, time-ordered event logs, or when you want shorter, URL-friendly identifiers. Use UUIDs when you need wider ecosystem compatibility.
Are ULIDs compatible with UUID columns?
Yes! A ULID is 128 bits, same as UUID. Most libraries can convert between ULID and UUID representations. You can store ULIDs in UUID database columns.
Is this tool free?
Yes, completely free. Everything runs in your browser — no data is sent to any server.