UUID Generator

Generate cryptographically random UUID v4 identifiers instantly. Copy individual UUIDs or all at once, toggle uppercase and hyphen formatting, and download as a text file.

Uppercase

A1B2C3… instead of a1b2c3…

Remove hyphens

a1b2c3d4… instead of a1b2-c3d4-…

Generated entirely in your browser — nothing is sent to any server.

Generated UUIDs0

Version 4 · RFC 4122 · random

Click a UUID to select · click to copy

About this tool

A fast, privacy-first UUID generator that runs entirely in your browser. Generate between 1 and 100 UUID v4 identifiers in a single click — formatted to your exact needs with uppercase and hyphen-removal toggles. Results update instantly as you change settings.

Uses the browser's built-in crypto.randomUUID() API for cryptographically strong randomness. No data is sent to any server, no signup required, and the tool works offline once the page has loaded.

How to use

1

Choose a count

Select how many UUIDs you need — 1, 5, 10, 50, or 100. The list updates instantly with fresh UUIDs.

2

Set your format

Toggle Uppercase to get capital hex letters. Toggle Remove Hyphens to get a compact 32-character string without dashes.

3

Copy or download

Click the clipboard icon next to any UUID to copy it individually. Use Copy All to copy the entire list, or Download .txt to save as a file.

4

Regenerate at any time

Click Regenerate or Refresh to generate a brand-new set of UUIDs with the same settings. Every UUID is cryptographically random.

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Frequently asked questions

Common questions about UUID v4, uniqueness guarantees, and formatting options.

UUID (Universally Unique Identifier) is a 128-bit label used to identify information in computer systems. They are used as primary keys in databases, session tokens, request trace IDs, file names, and anywhere a unique identifier is needed without central coordination. A properly generated UUID v4 is statistically guaranteed to be unique across all systems and time.

UUID v4 is randomly generated — 122 of its 128 bits are filled with random data. The remaining 6 bits are fixed according to RFC 4122 to mark the version (4) and variant. This makes v4 the simplest to generate and the most widely used version. It does not encode any timestamp or machine identity, making it safe for privacy-sensitive applications.

Yes, for all practical purposes. The probability of generating two identical UUID v4 values is approximately 1 in 5.3 × 10³⁶. You would need to generate about 2.7 quintillion UUIDs to have even a 50% chance of a collision. This generator uses the browser's built-in crypto.randomUUID() API, which is cryptographically strong.

A standard UUID looks like: 550e8400-e29b-41d4-a716-446655440000. The hyphens are part of the canonical textual representation defined in RFC 4122 and group the 32 hex characters into five sections (8-4-4-4-12). Removing hyphens gives a compact 32-character hex string: 550e8400e29b41d4a716446655440000. Both represent the same value — which format to use depends on your database or API requirements.

Yes. UUID v4 is one of the most common choices for distributed primary keys because generation requires no server coordination. The tradeoff versus sequential IDs is that UUID v4 is random, which can cause index fragmentation in some B-tree database engines (e.g. MySQL InnoDB). For high-insert-rate tables you may prefer UUID v7 (which is time-ordered) though this tool generates v4 only.

No. All UUIDs are generated using the Web Crypto API (crypto.randomUUID) directly in your browser. Nothing is sent to any server, and nothing is stored in cookies, localStorage, or any external system. You can use this tool offline once the page has loaded.

Yes. Toggle the Uppercase switch in the settings panel. The UUID value itself does not change — hex digits are case-insensitive — but uppercase formatting (A1B2C3D4-E5F6-4…) is sometimes required by legacy systems or style guides that expect capital letters.