NiftyKit

UUID v4 Generator

Create random version 4 UUIDs, one at a time or in batches.

By Updated

Runs in your browser. Your input is not uploaded.

1 to 1,000

Your UUIDs

    Press Generate to create UUIDs.

    What is a UUID?

    A UUID (universally unique identifier) is a 128-bit value used to identify something without needing a central authority to hand out numbers. They are written as 32 hexadecimal digits in five groups, like1b4e28ba-2fa1-41d2-883f-0016d3cca427.

    Developers use them as database primary keys, request and correlation IDs, file names, and anywhere two systems need to create identifiers independently without clashing.

    How this generator works

    This tool creates version 4 UUIDs, as defined in RFC 9562. Version 4 UUIDs are random: 122 of the 128 bits come from your browser’s cryptographically secure random number generator. The remaining six bits mark the version (the 4 at the start of the third group) and the variant (the first digit of the fourth group is always 8, 9, a or b).

    It uses crypto.randomUUID() where your browser supports it, and otherwise builds the UUID fromcrypto.getRandomValues(). It never falls back to Math.random(), which is not suitable for unique identifiers. UUIDs are generated on your device; nothing is sent to a server.

    How to use it

    1. Choose how many UUIDs you need, up to 1,000 at a time.
    2. Pick a style: lowercase is standard; uppercase and braces match some Microsoft tools.
    3. Press Generate. Copy a single UUID with the button beside it, or copy the whole batch.

    Changing the style options re-formats the current UUIDs without generating new ones.

    Frequently asked questions

    Are these UUIDs really unique?

    A version 4 UUID contains 122 random bits, so there are about 5.3 × 1036 possible values. You would need to generate around a billion UUIDs every second for roughly 85 years before having a 50% chance of a single duplicate. For practical purposes, they are unique.

    Is a UUID the same as a GUID?

    Yes. GUID (globally unique identifier) is the name Microsoft uses for the same 128-bit format. Some Windows tools show GUIDs in uppercase or wrapped in braces, like {1B4E28BA-2FA1-41D2-883F-0016D3CCA427}. Use the options above to match that style.

    Can I use these UUIDs as secret tokens or passwords?

    They are generated with a cryptographically secure random number generator, but UUIDs are designed to be identifiers, not secrets. They are often logged, shown in URLs and shared. For API keys, session tokens or passwords, use a purpose-built secret generator.

    Should I use UUID v4 or v7 for database keys?

    Version 4 UUIDs are fully random, which is simple and reveals nothing about when they were created. Version 7 UUIDs start with a timestamp, so they sort by creation time and can make database indexes more efficient. Version 4 remains the most widely supported choice.