Free UUID Generator — v4, v1 & v5
Updated July 2026
Generate UUID v4 (random), v1 (timestamp), or v5 (namespace) identifiers. Bulk generate up to 100 at once, copy with one click — free, runs in your browser.
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. UUIDs are designed to be globally unique without a central coordinator — two independently generated UUIDs will almost never collide, even across billions of records.
UUID versions explained
- v4 (random): 122 bits of randomness — the most common choice, best for new IDs with no ordering requirement
- v1 (timestamp): encodes the current timestamp — sortable by creation time but reveals when and roughly where it was generated
- v5 (namespace + name): a SHA-1 hash of a namespace UUID and a name string — deterministic, so the same input always produces the same UUID
When to use UUIDs
UUIDs are used as primary keys in distributed databases, session tokens, file identifiers, API resource IDs, and anywhere a unique identifier must be generated without coordination between servers. v4 is the safe default for most applications.
How the UUID Generator works
Select UUID version: v4 (random, most common), v1 (timestamp-based), or v5 (namespace + name).
Enter the quantity of UUIDs to generate (1 to 1,000).
Click Generate to produce your UUIDs instantly.
Copy all with one click, or click individual UUIDs to copy them separately.
Tips & tricks
- If the output looks wrong, verify that your input uses the correct syntax for the expected format.
- Minified or compressed inputs work fine — the UUID Generator pre-processes input before running the algorithm.
- Bookmark this page for instant access during debugging sessions. No login required on return visits.
Frequently Asked Questions
What is a UUID and when should I use one?
UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 8-4-4-4-12 hexadecimal characters (e.g. 550e8400-e29b-41d4-a716-446655440000). Use UUIDs as database primary keys, API resource IDs, and session tokens where uniqueness without central coordination is needed.
What is the difference between UUID v1 and v4?
UUID v1 includes a timestamp and MAC address — its creation time can be extracted. UUID v4 is fully random — it contains no traceable information, making it preferred for privacy-sensitive use cases.
Are generated UUIDs truly unique?
UUID v4 generates 2^122 possible values (≈5.3 × 10^36). The probability of two randomly generated UUID v4s colliding is astronomically small — generating 1 billion UUIDs per second for 100 years would have a ~50% chance of one collision.
What is UUID v5?
UUID v5 generates a deterministic UUID from a namespace UUID and a name using SHA-1 hashing. The same namespace + name always produces the same UUID — useful for creating stable identifiers for URLs or domain objects.
Can I generate UUIDs in uppercase format?
Yes. Toggle the uppercase option to output UUIDs in UPPERCASE hex (550E8400-E29B-41D4-A716-446655440000). Both forms are valid — case doesn't affect uniqueness.
Is the UUID Generator free to use?
Yes, the UUID Generator on Allio Tools is completely free with no sign-up or registration required. It works directly in your browser.
How does the UUID Generator work?
Generate UUID v4 (random), v1 (timestamp), or v5 (namespace) identifiers. Bulk generate up to 100 at once, copy with one click — free, runs in your browser. No data is sent to a server — everything runs locally in your browser for maximum privacy and speed.
Do I need to install anything to use the UUID Generator?
No installation needed. The UUID Generator runs entirely in your web browser on any device — desktop, tablet, or mobile.
Is my data safe when using the UUID Generator?
Completely safe. The UUID Generator processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.
Does the UUID Generator work offline?
After the page loads for the first time, the UUID Generator works without an internet connection for all client-side processing. Tools that fetch live external data (such as DNS or network lookups) require an active connection.
Can I use the UUID Generator output in commercial projects?
Yes. The UUID Generator is a utility tool and its output carries no licensing restrictions. You are free to use results in any project, commercial or personal.
Does the UUID Generator follow official standards?
Yes. The UUID Generator is built to comply with the relevant industry standard or specification for this utility type. If you encounter an unexpected result, verify your input against the specification — edge cases outside the standard may produce undefined behaviour.
Does the UUID Generator work on all browsers?
Yes. The UUID Generator is built with standard browser APIs and works on all modern browsers including Chrome, Firefox, Safari, and Edge — on both desktop and mobile. No plugins, extensions, or third-party software are required.
How do I save or export my results from the UUID Generator?
Select and copy the result text to paste into any document or app. For image tools, a Download button saves the file directly to your device. Your browser's built-in screenshot function also captures results quickly. No account or login is required.
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