UUID / GUID Generator

What is UUID Generator?

Free UUID v4 generator. Generate single or bulk UUID (GUID) identifiers instantly. Options for uppercase, braces format, and bulk export. Instant generators for passwords, QR codes, barcodes, and more. TekPulse's UUID Generator is completely free — no signup, no ads in results, and no data stored on our servers.

How to Use UUID Generator Online

1. Set the number of UUIDs to generate (1 to 1000)
2. Select version: UUID v4 (random) is the most commonly used
3. Click "Generate" — all UUIDs are created instantly using cryptographic randomness
4. Toggle "Uppercase" or "No Hyphens" formatting if required by your system
5. Copy all UUIDs to clipboard or download as a .txt file

UUID Generator Formula & Calculation

A UUID (Universally Unique Identifier) v4 is a 128-bit value, almost entirely generated from random bits, formatted as 32 hexadecimal digits in 5 groups separated by hyphens. Two fixed positions aren't random: the first digit of the third group is always '4' (marking this as version 4 — "randomly generated"), and the first digit of the fourth group is constrained to 8, 9, A, or B (marking the RFC 4122 'variant'). Everything else — all remaining 122 bits — comes from the browser's crypto.randomUUID(), which is backed by the same cryptographically secure random source as crypto.getRandomValues().

With 122 random bits, the number of possible UUIDs is 2¹²² ≈ 5.3 × 10³⁶. Even generating a billion UUIDs per second, the probability of ever generating a duplicate (a 'collision') is astronomically small — far lower than the odds of a hardware failure — which is why UUIDs are safe to use as database primary keys without checking for uniqueness.

Key Factors That Affect Your Result

1. Version 4 (random) vs. other versions — v1 UUIDs encode the generating machine's MAC address and a timestamp (a privacy leak and a source of ordering), while v4 is purely random, which is why it's the default choice for anonymous, decentralized ID generation (database keys, session tokens, distributed systems).
2. Collision probability — With 2¹²² possible values, you would need to generate roughly 2.71 quintillion UUIDs before there's a 50% chance of one collision (the "birthday problem" math) — in practice, collisions are a non-issue for any realistic application.
3. Format variants — Standard lowercase with hyphens is the RFC 4122 canonical form; uppercase, braces ({...}), and no-hyphens formats are purely cosmetic for compatibility with specific systems (e.g., Windows GUIDs commonly use braces and uppercase).
4. Not a substitute for sequential IDs — Because UUIDs are random, they don't sort chronologically and can fragment database indexes on insert-heavy tables; use auto-increment IDs or ULIDs instead when insertion order matters.

Why Use TekPulse UUID Generator?