About this tool
Need a batch of unique identifiers for database rows, test fixtures or correlation IDs? This generator produces standards-compliant UUIDs locally in your browser. Version 4 UUIDs are fully random, drawn from the browser's cryptographic random source, and are the default choice for most applications. Version 7 UUIDs embed a Unix millisecond timestamp in the high bits, giving you identifiers that sort roughly by creation time — a big win for database index locality, which is why v7 was standardized in RFC 9562 and adopted by modern systems. Generate one at a time or up to a thousand in a batch, toggle uppercase or hyphenless formatting, and copy the whole list with one click. Collision resistance comes from 122 bits of randomness per UUID, so generating identifiers offline here is exactly as safe as any server-side library. No IDs are logged or transmitted — they exist only in your browser tab until you copy them. Simple, fast, and correct.
How to use UUID Generator
- Pick a version: v4 for random UUIDs or v7 for time-ordered ones.
- Set how many you need, from 1 to 1000.
- Choose formatting: lowercase or uppercase, with or without hyphens.
- Press Generate and copy the results individually or all at once.
Frequently asked questions
What is the difference between v4 and v7?
v4 is fully random. v7 embeds a millisecond timestamp so IDs sort by creation time, which improves database index performance.
Are these UUIDs truly unique?
Each carries 122 bits of cryptographic randomness; the odds of a collision are astronomically small for any practical volume.
Is uppercase a different UUID?
No. Case is presentation only — A and a encode the same identifier. Hyphens are likewise cosmetic.
Do the UUIDs get sent to a server?
No. They are generated locally in your browser and never transmitted or logged.