Generate random UUID v4 or time-ordered UUID v7 identifiers, 1 to 1000 at once, as lowercase, uppercase or {braced} GUIDs. v4 uses crypto.randomUUID() (122 random bits); v7 (RFC 9562) leads with a 48-bit millisecond timestamp plus 74 random bits. IDs are minted on your device, never by a server.
Press Generate to create a UUID.
Waiting for Generate122 random bits·Generated on this device
A UUID (called a GUID on Windows and in .NET) is a 128-bit identifier written as 32 hex digits in an 8-4-4-4-12 pattern. Version 4 fills 122 of those bits with random data. Version 7 (RFC 9562) leads with a 48-bit millisecond timestamp and follows it with 74 random bits, so v7 IDs sort by creation time. Use v4 for request IDs, idempotency keys and anything that must not reveal when it was made; use v7 for database primary keys, where inserts in time order keep B-tree indexes compact.
How the UUID Generator works
Pick v4 or v7, set a count from 1 to 1000 and press Generate. v4 IDs come from crypto.randomUUID(). v7 IDs are assembled locally from Date.now(), a 12-bit counter that keeps same-millisecond IDs in generation order, and 62 bits from crypto.getRandomValues(). The formatting toggles (uppercase, no hyphens, {braces} for GUID-style .NET and registry values, quoted and comma-separated for SQL or JSON arrays) re-render the batch already on screen without regenerating it. Copy takes every line; .txt saves them as a file built in this tab. Nothing is requested from a server.
Limits
Up to 1,000 IDs per click.
~/faq
Frequently asked questions
What is the difference between a UUID and a GUID?
None in the bits: both are the same 128-bit format from RFC 9562 (formerly RFC 4122). GUID is Microsoft's name, used by Windows, .NET and SQL Server, where the value is usually shown in uppercase and wrapped in braces: {3F2504E0-4F89-41D3-9A0C-0305E82C3301}. Turn on Uppercase and {Braces} to get that spelling.
Should I use v4 or v7?
v7 for database primary keys: its 48-bit timestamp prefix means new rows land at the end of a B-tree index instead of on random pages, so inserts stay cheap and ORDER BY id approximates creation order. v4 for anything where the creation time must not leak (public tokens, share links, password-reset codes) or where ordering buys nothing, such as request and trace IDs.
How many can I generate at once?
Up to 1000 per click. Set the count, press Generate, then Copy all or save a .txt. A v7 batch is monotonic: sorted output equals generation order, even for IDs minted in the same millisecond.
Are these cryptographically random?
Yes. Both versions draw their random bits from the browser's Web Crypto CSPRNG: crypto.randomUUID() for v4, crypto.getRandomValues() for v7. That makes them unpredictable enough for identifiers, but a UUID is not a secret (v7 even prints its creation time in the first 12 hex digits), so do not use one as a password or session token.
Is anything sent to a server?
No. Generation, formatting, copying and the .txt download all happen in this tab. The page makes no request that carries the IDs; your browser's network panel shows none.
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