# UUID generator

URL: https://shahid09.is-a.dev/tools/uuid-generator/
Author: Muhammad Shahid (https://shahid09.is-a.dev/)
Free tool · runs in your browser

Generate random version 4 UUIDs, one at a time or in bulk, and copy them in the format you need.

**Quick answer:** A UUID (universally unique identifier) is a 128-bit ID written as 32 hexadecimal characters in five groups, like 3f2b8c1e-9a4d-4c7e-b5f0-1d2e3a4b5c6d. Version 4 UUIDs are random; this tool creates them with the browser's cryptographically secure random generator, so the chance of two being the same is negligible.

## How to use it

1. **Choose how many.** From 1 to 500.
2. **Pick a format.** Lowercase or uppercase, with or without dashes.
3. **Copy them.** One per line, ready to paste.

## Frequently asked questions

### Can two UUID v4 values be the same?

In theory yes, in practice no: there are about 5.3 × 10^36 possible version 4 UUIDs.

### What is the difference between UUID v4 and v7?

v4 is fully random. v7 starts with a timestamp, so values sort by creation time, which suits database primary keys.

### Is a UUID the same as a GUID?

Yes. GUID is Microsoft's name for the same 128-bit identifier.

### How do I generate a UUID in JavaScript?

crypto.randomUUID() in modern browsers and Node.js returns a version 4 UUID.

### Should I use UUIDs as database IDs?

They are fine when IDs must be unique across systems; for heavy write loads, time-ordered UUIDs (v7) index better than random v4.

### How is a UUID formatted?

32 hexadecimal characters in groups of 8-4-4-4-12. The first character of the third group shows the version, which is 4 for v4.

### Are UUIDs secure tokens?

Version 4 UUIDs from a secure generator are hard to guess, but for secrets such as password reset links, use a dedicated random token with enough length and an expiry.

### What is a nil UUID?

00000000-0000-0000-0000-000000000000, sometimes used as an empty value.

### How do I generate a UUID in Python?

import uuid, then uuid.uuid4().

### Are UUIDs case-sensitive?

No. Uppercase and lowercase represent the same value, though lowercase is the usual form.

## Related

- [Password generator](https://shahid09.is-a.dev/tools/password-generator/)
- [SHA-256 hash generator](https://shahid09.is-a.dev/tools/hash-generator/)
- [Unix timestamp converter](https://shahid09.is-a.dev/tools/unix-timestamp-converter/)