UUID Generator 🔒 Your data never leaves your browser.
Generate UUID v4 — single or in bulk, with formatting options.
v4 is fully random; v7 embeds a timestamp, so IDs sort by creation time.
Ctrl+EnterGenerate · Ctrl+SDownload
About this tool
A UUID v4 (Universally Unique Identifier) is a random 128-bit identifier in the form xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, with a practically zero chance of collision — used for database keys, session IDs, file names and more. In .NET it is commonly called a GUID. This UUID v7 generator can also produce UUID v7 IDs, which embed a millisecond timestamp so they sort by creation time — a better fit for database primary keys where insertion order matters.
This tool uses crypto.randomUUID() — the browser's built-in secure crypto API — so generated UUIDs are cryptographically random, and of course they never leave your machine.
Frequently asked questions
What's the difference between UUID v4 and v7?
v4 is fully random — 122 random bits with no structure. v7 embeds a millisecond-precision Unix timestamp in its first bits, so IDs generated later always sort after earlier ones, which makes v7 a good fit for database primary keys where you want time-ordered inserts.
Is the randomness cryptographically secure?
Yes — generation uses the browser's crypto.getRandomValues(), the same source used for cryptographic keys, not the weaker Math.random().
What does "Inspect" mode do?
Paste any UUID and it decodes the version, variant, canonical (lowercase, hyphenated) form and, for version 1, 6, or 7 UUIDs, the embedded timestamp shown both as ISO 8601 and in your local time.
Can I generate UUIDs without hyphens or in uppercase?
Yes — toggle "No hyphens" and "Uppercase"; both apply to bulk generation too, for up to 10,000 UUIDs at once.
Are the UUIDs I generate or inspect sent anywhere?
No — both generation and parsing happen entirely in your browser; nothing is uploaded to a server.
What is UUID v7 and how is it different from v4?
UUID v7 was standardized alongside v4 in RFC 9562 (2024): instead of being fully random, it puts a 48-bit millisecond Unix timestamp in the leading bits, so IDs created later always sort after IDs created earlier — great for database primary keys and log identifiers where insertion order and index locality matter. v4 has no such structure, which is exactly the point when you need an identifier that leaks nothing about when it was created, such as a public-facing token or a password-reset link. As a rule of thumb: reach for v7 when time-ordering helps your storage engine, and v4 when unpredictability is the priority.