Free Online UUID Generator
Generate UUID v1 and v4 values individually or in bulk.
Choose a number from 1 to 100.
Version 4 UUIDs use a cryptographically secure random source. Version 1 UUIDs combine a timestamp with a random node and clock sequence, so no network address is exposed.
Each value is RFC 4122 compliant and ready for databases, APIs, and test fixtures.
About the UUID Generator
A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122 and later RFC 9562. UUIDs are designed to be generated independently on different machines without a central coordinator, which makes them popular for database primary keys, distributed systems, message IDs, session tokens, and test data. This generator creates version 1 and version 4 UUIDs entirely in your browser.
Version 4 versus version 1
- Version 4: 122 bits come from a random source. When
crypto.randomUUID()is available it is used directly; otherwise the tool fills 16 random bytes withcrypto.getRandomValues()and sets the version and variant bits itself. - Version 1: the identifier contains a 60-bit timestamp counted in 100-nanosecond intervals since 15 October 1582, a 14-bit clock sequence, and a 48-bit node value. We generate a random node with the multicast bit set instead of exposing a real MAC address.
Both versions are formatted as eight, four, four, four, and twelve hexadecimal digits. The hyphenated form is the canonical presentation, but many databases and URLs store the 32-character form without hyphens. Use the toggles to switch between the two, and switch to uppercase if a system expects it. Counts from one to one hundred are supported, so you can generate a single key or a bulk fixture list.
Random v4 identifiers are generally the safest default because they leak no time or host information. Version 1 values are sortable by creation time, which can help index locality, but they reveal roughly when they were created. If you need time-ordered identifiers, consider UUID v7, which places a Unix timestamp at the front while remaining mostly random. In every case, UUIDs are identifiers, not secrets; never use one as a password or authentication token.
How to use this tool
- Pick version 1 or version 4.
- Set the count between 1 and 100.
- Choose uppercase letters and whether to keep hyphens.
- Click Generate, then copy the list or download it as a text file.
Frequently asked questions
Are generated UUIDs truly unique?
No identifier can guarantee absolute uniqueness, but version 4 has 122 random bits, making collisions astronomically unlikely. Version 1 combines a high-resolution timestamp with a node and clock sequence.
Does version 1 expose my MAC address?
Not here. This tool creates a random node value and sets the multicast bit, which is the privacy-preserving approach recommended for software-generated UUIDs.
Can I use these UUIDs as security tokens?
They are not designed as secrets. Use a dedicated cryptographic token generator for passwords, API keys, or session identifiers.