UUID Generator
Generate cryptographically random UUID v4 values in bulk. Copy individual UUIDs or all at once.
UUIDs (Universally Unique Identifiers) are 128-bit identifiers designed to be unique without coordination — no central server needed. They are used as primary keys in distributed databases, identifiers for transactions, file names, session IDs, and anywhere you need a unique value that two independent systems cannot accidentally produce at the same time. UUID v4 (random) is the most commonly used version, and this generator creates cryptographically random UUIDs using the browser's secure random number generator.
📋 How to Use This Calculator
Select how many UUIDs you need — 1, 5, 10, or 20 — and click "Generate UUID v4." The tool generates the requested number of cryptographically random UUIDs. Hover over any UUID to see the individual Copy button, or use "Copy All" to copy all UUIDs separated by newlines. Click the button multiple times to generate fresh batches. Each UUID is unique and generated fresh every time — you will never get a duplicate in practice (the probability of collision is astronomically low: about 1 in 10³⁰ for 1 billion UUIDs).
💡 Key Facts & Information
UUID v4 format is xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where x is a random hex digit, 4 is the version number, and y is one of 8, 9, a, or b (the variant bits). A UUID contains 122 random bits (4 bits fixed for version, 2 for variant). The namespace of possible UUIDs is 2¹²² ≈ 5.3 × 10³⁶. This generator uses crypto.randomUUID() — the Web Crypto API's UUID function — which is seeded from OS-level entropy (the same source used for cryptographic keys). This is far more secure than Math.random()-based UUID generators, which are not cryptographically random.