Generators · Free online tool

UUID Generator (v1 & v4)

Generate single or bulk UUID v1 and v4 identifiers with uppercase, compact, and copy-all options.

Quick answer: Choose UUID v4 for random identifiers or v1 for timestamp-based identifiers, set a quantity, and press Generate. Copy one value or the full list.

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How this uuid generator helps

This UUID generator creates RFC 4122-style version 1 and version 4 identifiers directly in the browser. Version 4 uses cryptographically secure random values and is the right default for application IDs, database keys, test fixtures, correlation IDs, and temporary object names. Version 1 combines timestamp and node-style data and can be useful when chronological construction is required by a legacy system. You can generate up to 100 values at once, choose lowercase or uppercase, remove hyphens, and copy individual results or the complete list. No remote service is involved and no generated value is transmitted. The interface explains the version and variant bits so users understand what they are copying. It is lightweight enough for quick development work and transparent enough for teams that need to avoid opaque online generators.

Last updated: 2026-08-31. All processing happens locally; no tool input is sent to a server.

Real-world examples

Seed a database

Generate a batch of v4 UUIDs for local fixtures or integration tests.

Create test identifiers

Generate uppercase or compact IDs that match a legacy format.

Compare UUID versions

Generate v1 and v4 examples and inspect their structure side by side.

Frequently asked questions

Should I use UUID v1 or v4?

Use v4 for most new systems because it is random and simple. Use v1 only when timestamp-based construction is required.

Are generated UUIDs unique?

V4 UUIDs have an extremely low collision probability. Uniqueness is not mathematically guaranteed, so enforce database constraints when required.

Are these UUIDs sent anywhere?

No. They are generated locally using browser cryptographic APIs and never leave your device.

Is a UUID the same as a GUID?

GUID is Microsoft terminology for a globally unique identifier and is commonly represented in the same textual format as a UUID.