Uuid Generator

Free online tool. All processing is client-side. No signup needed.

How to Use the Uuid Generator

1. Enter your input values above
2. Results update automatically
3. Copy or download the output

What is a Uuid Generator?

A UUID Generator creates universally unique identifiers — 128-bit values that are (practically) guaranteed to be unique across all space and time without a central registration authority. UUIDs are essential in software development for database primary keys, distributed systems, API request tracking, file naming, and anywhere you need a unique ID that won't collide. The most common version, UUID v4, generates random UUIDs with 122 bits of randomness — the probability of collision is so low you'd need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of a single collision.

How Does It Work?

Select your UUID version: v1 (time-based, contains MAC address + timestamp — useful for ordering), v4 (random — most common), or v7 (time-ordered with random suffix, new in 2024 — best for database indexes). The generator creates the UUID following RFC 9562 (updated 2024) format: 8-4-4-4-12 hexadecimal characters separated by hyphens, e.g., 550e8400-e29b-41d4-a716-446655440000. Batch generation mode creates up to 100 UUIDs at once.

Formula

UUID Format: xxxxxxxx-xxxx-Vxxx-yxxx-xxxxxxxxxxxx\n\nWhere:\nV = Version number (1,4,7)\ny = Variant (8,9,A,B for RFC 9562)\n\nUUID v4: 122 random bits + 6 version/variant bits\nUUID v7: 48-bit Unix timestamp (ms) + 74 random bits\n\nTotal possible UUIDs: 2¹²² ≈ 5.3 × 10³⁶ (v4)\nCollision probability (1B UUIDs): ~1 in 10¹⁸

Who Uses This Tool?

• Database developers generating conflict-free primary keys across distributed systems
• Web developers assigning unique IDs to HTML elements or API resources
• System administrators naming servers, files, or log entries uniquely
• API developers creating idempotency keys or request tracking IDs
• Game developers generating unique entity or player identifiers

Pro Tips

• Use UUID v7 for database primary keys — it's time-ordered, which improves B-tree index performance over v4's random ordering
• UUIDs as string primary keys use more storage and are slower than auto-increment integers. Consider ULID (also available on this site) as a more compact alternative
• For REST APIs, always accept UUIDs in standard format AND without hyphens. Strip hyphens and re-add for validation
• UUID v1 contains your MAC address — avoid using it for public-facing IDs where privacy matters. Stick with v4 or v7

Frequently Asked Questions about Uuid Generator

Are UUIDs truly unique?

For practical purposes, yes. UUID v4 has 122 random bits, creating ~5.3 undecillion (10³⁶) possible values. The chance of a duplicate is astronomically lower than being struck by a meteor. v1 and v7 add timestamps, making collisions impossible within the same system.

UUID v4 vs v7: which should I use?

UUID v4 (random) is the most common and well-supported. UUID v7 (time-ordered + random) is better for database primary keys because it sorts chronologically, reducing index fragmentation. v7 was standardized in RFC 9562 (2024) and is gaining support in modern frameworks.

Free online Uuid Generator — no signup, 100% client-side processing. All data stays in your browser.