UUID generator

Make v4 and v7 UUIDs in your browser

Runs in your browser. Nothing is uploaded.

How it works

A UUID is a 128-bit ID that’s effectively unique without any central list. Version 4 is random, and it’s the common choice. Version 7 starts with the time, so IDs sort in the order they were made, which suits database keys. These are made with your browser’s secure random generator, up to 1,000 at a time.

v4 is 122 random bits. v7 starts with the time, then random bits.

Each ID is made in your browser using its secure generator. If that isn’t available, we show an error, because we won’t use a weaker source.

Worked example. A v4 ID looks like 3f2b8c1e-9a4d-4e7b-b1c2-8d5e6f7a9b0c. The 4 after the second dash marks the version.

Examples

Version	Best for
v4	General use
v7	Database keys, because they sort by time

What this tool doesn’t cover

A v7 ID reveals roughly when it was made.

Questions

Should I use v4 or v7?

Use v7 for database keys, because it sorts by time. Use v4 when you don’t want the time to show.

Can two UUIDs clash?

In practice, no. The odds are too small to matter.

Is a UUID a secret?

No. Don’t use one in place of a password or a security token.

What is a UUID?

A universally unique identifier: a 128-bit value, shown as 36 characters. It lets systems make IDs without asking a central server.

What is the difference between a UUID and a GUID?

Nothing in practice. GUID is Microsoft’s name for the same idea.

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Built by QuickToolz.

Sources: RFC 9562: Universally Unique IDentifiers (opens in a new tab)