UUID Generator
Generate one or many random UUID v4 identifiers instantly, with one-click copy. Free and in-browser.
How to use the UUID Generator
- 1Open the UUID Generator; a valid v4 UUID appears immediately, ready to copy.
- 2Set the quantity field to how many you need (for example 1, 50, or 500) to produce a single ID or a full batch.
- 3Click Generate to mint a fresh set; each click discards the previous list and draws brand-new random identifiers.
- 4Click the copy icon beside any single UUID to place just that value on your clipboard.
- 5Use Copy All to grab the whole batch as newline-separated text, ready to paste into code, a database seed, or a spreadsheet.
- 6Toggle uppercase or hyphen-free formatting if your target system requires it, then copy the adjusted output.
About the UUID Generator
A UUID Generator creates version 4 universally unique identifiers: 128-bit values written as 36-character strings like 3f2504e0-4f89-41d3-9a0c-0305e82c3301. A v4 UUID carries 122 random bits plus a fixed version digit (the 4 that opens the third group) and two variant bits. This tool draws those random bits from your browser's cryptographically strong crypto.getRandomValues(), or calls the native crypto.randomUUID() where the browser exposes it, then formats the result exactly as RFC 4122 (and its successor RFC 9562) specifies. All of that runs in JavaScript on your own device. Nothing is uploaded, logged, or transmitted, so even an identifier you intend to treat as a secret token never leaves your machine, and the page keeps generating offline once it has loaded.
The point of v4 is that any machine can mint an identifier without asking a central database or coordination service for the next value. Two independent processes can each generate one and the chance they collide is negligible, which is why developers use v4 UUIDs as primary keys created client-side before an insert, as idempotency keys on payment and API calls, as filenames for uploaded assets, as correlation IDs for tracing a request across microservices, and as stable keys in React lists or test fixtures.
Bulk output is where this tool earns its place. Instead of writing a throwaway script, set a count and get 1, 100, or a few thousand IDs in one pass, then copy the whole batch as newline-separated text or lift a single value with the copy icon beside it. Optional toggles switch to uppercase or strip the hyphens when a target system demands it. Two things worth remembering: store UUIDs in a native uuid or 16-byte binary column rather than char(36), which nearly halves the space and speeds up index lookups; and v4 is random, not time-ordered, so sorting the list tells you nothing about creation order. If you need identifiers that sort chronologically, generate UUID v7 instead or keep a separate created_at timestamp.
Frequently asked questions
How can I confirm the output is a version 4 UUID and not another version?
Look at the first character of the third hyphen-separated group; in a v4 UUID it is always the digit 4, and the first character of the fourth group is 8, 9, a, or b (the variant bits). This tool sets both explicitly, so every ID it produces passes that check. The remaining 122 bits are random.
If I generate a few thousand at once, could two of them be identical?
In practice, no. With 122 random bits from a cryptographic source, you would need to generate on the order of a billion UUIDs before a single collision became statistically likely, so a batch of a few thousand carries no realistic risk. The tool does not de-duplicate the list because it does not need to.
Can I sort these UUIDs to recover the order they were created in?
No. Version 4 UUIDs are fully random, so sorting them alphabetically produces a meaningless order and, as random primary keys, they also scatter B-tree index inserts. If you need time-ordered identifiers, generate UUID v7 or store a separate created_at column next to the UUID.
Is the randomness strong enough to use a generated UUID as a security token?
The 122 random bits come from the browser's cryptographically secure generator (crypto.getRandomValues / crypto.randomUUID), so a v4 UUID is genuinely hard to guess and fine as, say, a one-time link or lookup key. For long-lived session or API secrets, many teams still prefer a purpose-built token with more entropy, but v4 is a reasonable unpredictable choice.
Does generating a large batch send anything to a server or count against a rate limit?
No. Generation happens entirely in your browser, so no UUID is transmitted, stored, or logged anywhere, there is no API to rate-limit, and the tool keeps working with your network disconnected once the page has loaded.
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Frequently asked questions
How many can I generate?+
Generate a single UUID or a bulk list, then copy them all.