UUID Generator

Generate UUIDs (v4)
This free online uuid generator runs in your browser and is part of our Generators collection.

⚡ UUID Generator

Generate Universally Unique Identifiers (Version 4)

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information. UUIDs are practically guaranteed to be unique across space and time.

Example: 550e8400-e29b-41d4-a716-446655440000

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Instant In-Browser Execution Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever No subscription fees, no signups, and no software installations.

How to Use the Online UUID Generator

1 Select UUID Version & Count

Generate standard RFC 4122 Version 4 (v4) random UUIDs, and set the batch quantity (from 1 to 500 UUIDs).

2 Choose Formatting Options

Toggle Uppercase vs Lowercase letters, and choose whether to include standard hyphens (`8-4-4-4-12` format) or raw 32-character strings.

3 Include Enclosing Braces or Quotes

Optionally format output with curly braces `{...}` or SQL/JSON quotes for instant paste into database seeds.

4 Generate & Copy Output

Click "Generate UUIDs" to run entropy sampling and copy the generated identifiers to your clipboard.

Frequently Asked Questions

Common questions about using this free online uuid generator.

What is a Version 4 (v4) UUID? ▾
A v4 UUID is a 128-bit identifier composed of 32 hexadecimal digits and 4 hyphens (36 characters total). It contains 122 bits of cryptographically random entropy, with 6 bits reserved for version and variant flags.
What are the chances of two v4 UUIDs colliding? ▾
Virtually zero. You would need to generate 1 billion UUIDs every second for approximately 85 years to have a 50% probability of a single collision.
Are these UUIDs safe for database primary keys? ▾
Yes. UUID v4 is widely used in PostgreSQL (`gen_random_uuid()`), MySQL, MongoDB, and distributed microservices where generating unique IDs without a centralized coordinator is required.
Does this generator use the browser native `crypto.randomUUID()`? ▾
Yes. On modern browsers, it utilizes the native high-performance `crypto.randomUUID()` API function with CSPRNG fallback.

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