UUID Generator
The UUID Generator creates universally unique identifiers (UUIDs) according to RFC 4122. UUIDs are 128-bit identifiers that are practically guaranteed to be unique without coordination between systems. They are widely used in databases, distributed systems, file naming, and API design. This generator supports multiple UUID versions: UUIDv4 (random, most common), UUIDv1 (time-based), and nil UUID. Each UUID is represented as 32 hexadecimal digits in 8-4-4-4-12 format.
Formula
UUID format: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx M = version (4 for random) N = variant (8, 9, a, or b) UUIDv4: random 122 bits Collision probability: ~0 for practical purposes Total UUIDs: 2^122 = 5.3 x 10^36
Example
UUIDv4 (random): 550e8400-e29b-41d4-a716-446655440000 Another UUIDv4: f47ac10b-58cc-4372-a567-0e02b2c3d479 Nil UUID: 00000000-0000-0000-0000-000000000000
How to Use
- Select UUID version (v4 for random, v1 for time-based)
- Choose how many UUIDs to generate
- Click generate to create UUIDs
- Copy individual UUIDs or all at once
- Use in databases, APIs, or distributed systems
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is practically guaranteed to be unique. UUIDs are used in databases, distributed systems, APIs, and anywhere a unique identifier is needed without central coordination.
What is the difference between UUIDv1 and UUIDv4?
UUIDv1 is based on the current timestamp and MAC address. UUIDv4 is completely random. UUIDv4 is preferred for most use cases because it does not leak machine information and is not predictable. UUIDv1 can be useful when chronological ordering matters.
Are UUIDs really unique?
Yes, for practical purposes. UUIDv4 has 2^122 possible values. The probability of a collision in 103 trillion UUIDs is one in a billion. You would need to generate billions of UUIDs per second for centuries to have a reasonable chance of collision.
Should I use UUIDs as database primary keys?
Yes, UUIDs are excellent primary keys for distributed systems. They allow multiple systems to generate IDs without coordination. However, UUIDs are larger than sequential integers (16 bytes vs 4 bytes) and can cause index fragmentation. Consider UUIDv7 for time-ordered UUIDs.
Can I generate multiple UUIDs at once?
Yes, this generator can create multiple UUIDs in a single click. You can generate 1, 5, 10, or 100 UUIDs at once. Each is independently random and guaranteed to be unique.