Free Toolkit

ULID GeneratorGenerate sortable ULID identifiers with embedded timestamps.

ULID Generator illustration
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ULID Generator

Generate sortable ULID identifiers with embedded timestamps.

How to Use
1

Set Options

Choose quantity and case preferences.

2

Generate

Type anything to generate ULIDs.

3

Copy ULIDs

Copy the generated ULIDs from the output.

What Is ULID Generator?

A ULID (Universally Unique Lexicographically Sortable Identifier) generator creates 128-bit identifiers that are both unique and sortable by creation time. Unlike UUIDs, ULIDs encode a millisecond-precision timestamp in the first 48 bits, followed by 80 bits of randomness. This means ULIDs generated later always sort after earlier ones, making them ideal for database primary keys, event logs, and any use case where chronological ordering matters. ULIDs use Crockford's Base32 encoding, producing compact 26-character strings that are URL-safe and case-insensitive.

Why Use Our ULID Generator?

  • Sortable by creation time — newer IDs always sort after older ones
  • Compact 26-character string using Crockford Base32
  • URL-safe and case-insensitive
  • Compatible with UUID 128-bit storage
  • Embedded millisecond-precision timestamp

Common Use Cases

Database Primary Keys

Use ULIDs as sortable primary keys that maintain insertion order without additional timestamp columns.

Event Sourcing

Generate ordered event IDs that naturally sort chronologically.

Distributed Systems

Create unique IDs across services that maintain global ordering by time.

Log Entries

Assign sortable IDs to log entries for easy chronological querying.

Technical Guide

ULID format is a 26-character Crockford Base32 string: 10 characters for the 48-bit timestamp (milliseconds since Unix epoch) and 16 characters for 80 bits of randomness. The timestamp component encodes creation time and provides sorting — ULIDs generated in the same millisecond are further ordered by their random component. Crockford Base32 uses characters 0-9 and A-Z excluding I, L, O, U to avoid ambiguity. The encoding is more compact than hex (26 chars vs UUID's 36) while maintaining the same 128-bit information content. The implementation uses crypto.getRandomValues() for the random portion.

Tips & Best Practices

  • 1
    ULIDs sort lexicographically by creation time — great for database ordering
  • 2
    The first 10 characters encode the timestamp — you can extract creation time
  • 3
    ULIDs are case-insensitive; lowercase option is for stylistic preference
  • 4
    At 26 characters, ULIDs are more compact than 36-character UUIDs
  • 5
    ULIDs can be stored in UUID-compatible 16-byte binary columns

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Frequently Asked Questions

QHow is ULID different from UUID?
ULIDs are lexicographically sortable by creation time, more compact (26 vs 36 chars), and URL-safe. UUIDs are random and don't sort by time.
QCan ULIDs collide?
With 80 random bits per millisecond, collision probability is about 1 in 2^80 for IDs generated in the same millisecond.
QCan I extract the timestamp from a ULID?
Yes, the first 10 characters encode the creation timestamp in milliseconds since Unix epoch.
QAre ULIDs URL-safe?
Yes, ULIDs use only alphanumeric characters (Crockford Base32) and are safe for use in URLs without encoding.
QWhich should I use — UUID or ULID?
Use ULID when you need sortable IDs (database keys, event logs). Use UUID when ordering doesn't matter or for compatibility with existing UUID systems.

About ULID Generator

ULID Generator is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.