UUID Generator

How to use UUID Generator

1. 1
   Choose how many UUIDs to generate

   Use the count slider to select anywhere from 1 to 100 UUIDs. The default is 1 for a single identifier.

2. 2
   Select formatting options

   Toggle between uppercase and lowercase output. Optionally remove hyphens to get a compact 32-character string.

3. 3
   Click Generate

   Press the Generate button to create cryptographically random UUID v4 values using your browser's built-in crypto API.

4. 4
   Copy individual UUIDs

   Click the copy icon next to any UUID to copy just that one value to your clipboard.

5. 5
   Copy all at once

   Use the Copy All button to copy every generated UUID to your clipboard, one per line — ready to paste into code or a spreadsheet.

Frequently Asked Questions

What is a UUID?

UUID (Universally Unique Identifier) is a 128-bit identifier standardised by RFC 4122. UUID v4 is randomly generated, producing values like '550e8400-e29b-41d4-a716-446655440000'. The probability of two random v4 UUIDs colliding is astronomically small — roughly 1 in 5.3 × 10³⁶.

Are these UUIDs truly random?

Yes. This tool uses the browser's built-in crypto.randomUUID() API, which draws from the same cryptographically secure random number generator used for TLS and other security functions. It is safe to use these UUIDs as database primary keys or session tokens.

Is my UUID generation private?

Completely. All UUIDs are generated locally in your browser. Nothing is sent to any server. You can use this tool completely offline once the page has loaded.

What is the difference between UUID v4 with and without hyphens?

A standard UUID v4 is 36 characters with hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). Removing hyphens gives a compact 32-character hex string (e.g., 550e8400e29b41d4a716446655440000). Both represent exactly the same value — the choice depends on your system's storage format.

Can I use UUID v4 as a database primary key?

Yes. UUID v4 is widely used as a distributed, collision-resistant primary key — especially in microservices where multiple services create records without a central auto-increment sequence. For write-heavy databases, consider UUID v7 (time-ordered) to avoid index fragmentation, though v4 remains the most common choice.

What is the format of a UUID v4?

A UUID v4 follows the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where 4 indicates version 4 and y is one of 8, 9, a, or b (indicating RFC 4122 variant). The remaining 122 bits are random.

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