Version:
How many?
Generated UUIDs
What This Tool Does
The UUID Generator creates version 4 (random) and version 1 (time-based) UUIDs using the browser's crypto.randomUUID() API or crypto.getRandomValues() as a fallback. Both are cryptographically secure. You can generate up to 100 UUIDs at a time and copy them individually or all at once.
How to Use
1. Select v4 (random) or v1 (time-based).
2. Set the quantity (1–100).
3. Choose formatting options (uppercase, braces, no hyphens).
4. Click Generate UUIDs.
5. Copy individual UUIDs with the copy icon, or click Copy All.
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier), is a 128-bit identifier formatted as 32 hexadecimal digits in the pattern 8-4-4-4-12 (e.g. 550e8400-e29b-41d4-a716-446655440000). They are designed to be unique across all space and time without a central registry.
What is the difference between UUID v1 and v4?
UUID v1 is generated from the current timestamp and the device's MAC address (or a random node ID in browsers). It is time-sortable, meaning UUIDs generated later are lexicographically larger. UUID v4 is fully random (using crypto.randomUUID() or crypto.getRandomValues()) and is the most widely used version — preferred when you do not need time ordering.
Are UUID v4s truly unique?
The probability of two random v4 UUIDs colliding is astronomically small — approximately 1 in 5.3 × 10^36. For all practical purposes they are unique. You would need to generate about 2.7 quintillion UUIDs before having a 50% chance of a single collision.
What is a UUID used for?
Common uses include primary keys in databases, identifiers in distributed systems (where sequential IDs would conflict), session tokens, file names, correlation IDs in logging, and anywhere a globally unique identifier is needed without a central coordinator.
Is GUID the same as UUID?
Yes — GUID (Globally Unique Identifier) is Microsoft's name for UUID. They use the same format and are interchangeable. The UUID standard is defined by RFC 4122.