UUID Generator
Generate universally unique identifiers in version 4 (random) or version 7 (time-ordered), using your browser’s cryptographic random number generator.
What is a UUID Generator?
A UUID is a 128-bit universally unique identifier, written as five groups of hexadecimal digits separated by hyphens — for example, 550e8400-e29b-41d4-a716-446655440000. Developers use UUIDs as database primary keys, file names for uploads, request ids, and test data, anywhere a value must be unique without coordinating with a central counter.
Version 4 is fully random: 122 bits of cryptographic randomness make collisions so unlikely they can be ignored in practice. Version 7 is newer and time-ordered: its first 48 bits are the current Unix time in milliseconds, followed by a version nibble of 7, variant bits, and random bits. Because the timestamp leads, version 7 ids generated later sort after earlier ones, which keeps database indexes efficient — a real advantage over random version 4 ids at scale. Both versions here are generated with crypto.getRandomValues, the browser's cryptographic random source.
How to use the UUID Generator
1. Pick a version: v4 for plain random ids, or v7 when you want ids that sort in creation order. 2. Choose how many to generate: 1, 5, 10, 20, or 50. 3. Optionally tick Uppercase or No hyphens for systems that expect that format. 4. Click Generate, then Copy all to take the list to your clipboard. Results are not saved anywhere, so copy them before leaving the page.
Frequently asked questions
Should I use v4 or v7? Use v7 for new database keys and event ids: time ordering improves index performance and the ids remain globally unique. Use v4 when you need an opaque id with no embedded timestamp, or when a system specifically requires version 4.
Can two generated UUIDs collide? For v4, the random space has about 5.3 × 10³⁶ combinations — effectively never in normal use. For v7, ids from the same millisecond also carry 74 random and variant bits, so collisions remain negligible.
Why do results change on refresh? That is the point of a UUID: every generation produces fresh, unique values. This page stores nothing, so copy your results before refreshing or leaving.
Does the no-hyphens format still count as a UUID? It is the same 128 bits written as 32 hexadecimal characters without separators. Many systems accept that compact form, but strict validators may require the hyphenated 8-4-4-4-12 layout.
Related tools
Hash Generator · Timestamp Converter · Base64 Encode & Decode · Word Counter