ULID Generator
Generate Universally Unique Lexicographically Sortable Identifiers
What is ULID?
ULID (Universally Unique Lexicographically Sortable Identifier) is a 128-bit identifier that is time-sortable and compatible with UUID.
Suggested Next Steps
Related Tools
QR Code Generator
Generate QR codes quickly for URLs, text, WiFi, and more.
UUID Generator
Generate random UUID/GUID identifiers
Random Hex Generator
Generate random hexadecimal numbers with custom length and count
AI README Generator
Generate professional README files with AI
.gitignore Generator
Generate .gitignore files for your project
AI Dockerfile Generator
Generate optimized Dockerfiles with AI
How to Use
Enter Your Values
Fill in the input fields with your numbers or parameters.
Get Instant Results
Results update automatically as you type — no submit button needed.
Copy or Save
Copy results to clipboard or use them in your workflow.
Why Use This Tool
100% Free
No hidden costs, no premium tiers — every feature is free.
No Installation
Runs entirely in your browser. No software to download or install.
Private & Secure
Your data never leaves your device. Nothing is uploaded to any server.
Works on Mobile
Fully responsive — use on your phone, tablet, or desktop.
ULID: Universally Unique Lexicographically Sortable Identifiers
Key Takeaways
- ULIDs combine a 48-bit millisecond timestamp with 80 bits of randomness, creating IDs that are both unique and chronologically sortable.
- ULIDs use Crockford's Base32 encoding, producing compact 26-character strings that are URL-safe and case-insensitive.
- All ULIDs are generated in your browser — no data is sent to any server.
ULID (Universally Unique Lexicographically Sortable Identifier) addresses a key limitation of UUID v4: lack of natural ordering. By encoding the creation timestamp in the first 10 characters, ULIDs sort chronologically while maintaining global uniqueness through random suffixes. This makes them excellent primary keys for databases where insertion order matters.
ULIDs can generate 1.21 x 10^24 unique IDs per millisecond — more than enough for any application.
Throughput Capacity
Key Concepts
ULID Structure
A ULID consists of a 10-character timestamp (48 bits, millisecond precision, good until year 10889) followed by a 16-character random component (80 bits of entropy).
Crockford's Base32
ULIDs use Crockford's Base32 alphabet (0-9, A-Z excluding I, L, O, U) which avoids ambiguous characters. This encoding is URL-safe, case-insensitive, and more compact than hex.
ULID vs. UUID v7
Both embed timestamps for sortability. UUID v7 is an official IETF standard (RFC 9562) with broad ecosystem support. ULIDs are more compact (26 vs 36 chars) and use a simpler specification.
Monotonic ULIDs
When multiple ULIDs are generated within the same millisecond, monotonic mode increments the random component to guarantee strict ordering within that millisecond.
Pro Tips
Use ULIDs as database primary keys when you need time-ordered records without a separate created_at column.
Extract the timestamp from existing ULIDs for audit logging — no additional metadata storage needed.
Use monotonic ULID generation in high-throughput systems to guarantee strict ordering even at sub-millisecond rates.
ULIDs can be converted to UUID format (128-bit) for compatibility with UUID-typed database columns.
All ULIDs are generated entirely in your browser using cryptographically secure randomness. No generated identifiers are stored or transmitted to any server.