Uses crypto.randomUUID() with 122 bits of cryptographic randomness for maximum uniqueness.
Generate up to 1,000 UUIDs at once. Copy all or download as a TXT file.
Standard (with dashes), no dashes, UPPERCASE, or UPPERCASE without dashes.
Copy individual UUIDs or all generated UUIDs to clipboard with a single click.
Export bulk-generated UUIDs as a plain text file, one UUID per line.
All generation happens locally in your browser. No UUIDs are sent to any server.
Select from standard (8-4-4-4-12 with dashes), no dashes, UPPERCASE, or UPPERCASE without dashes.
Click "Refresh" to generate a single UUID instantly. Click the clipboard icon to copy it.
Enter a count (1-1000) and click "Generate" to create multiple UUIDs at once.
Use "Copy All" to copy all UUIDs to clipboard, or "Download TXT" to save them as a file.
| Version | Generation Method | Sortable | Best For |
|---|---|---|---|
| UUID v1 | Timestamp + MAC address | Partially | Legacy systems, audit trails |
| UUID v3 | MD5 hash of namespace + name | No | Deterministic IDs from names |
| UUID v4 | Cryptographic random (122 bits) | No | General purpose, most common |
| UUID v5 | SHA-1 hash of namespace + name | No | Deterministic IDs (preferred over v3) |
| UUID v7 | Unix timestamp + random | Yes | Database primary keys, time-ordered |
This tool generates UUID v4 (random), the most widely used version for general-purpose unique identifiers.
Generate random UUIDs (Universally Unique Identifiers) online free with FreeToolBox — create version 4 (random) UUIDs instantly for use as database primary keys, API request identifiers, session tokens, correlation IDs, and unique file names. UUIDs are 128-bit values defined by RFC 4122, formatted as 32 hexadecimal characters separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). With 122 bits of cryptographic randomness in UUID v4, the probability of collision is approximately 1 in 5.3 × 10^36 — making them safe for independent generation across distributed systems without any central coordination.
This tool generates UUIDs using the browser's native crypto.randomUUID() API, which provides cryptographically secure pseudo-random numbers. Generate a single UUID with one click, or bulk-generate up to 1,000 UUIDs at once. Choose from four output formats: standard with dashes, without dashes, UPPERCASE, or UPPERCASE without dashes. Copy individual UUIDs, copy all at once, or download the list as a TXT file. All generation is local — no data leaves your browser. Completely free, instant, no account required.
Use UUID Generator when you need collision-resistant identifiers, not human-memorable secrets. If you need random credentials instead, use Password Generator. If you need a deterministic digest of existing content, use Hash Generator.
No-upload workflow: IDs for internal datasets, testing, and app workflows stay local in your browser.
UUIDs are useful when IDs must be generated independently across multiple systems, clients, or services without central coordination. Auto-incrementing IDs are shorter, but they are predictable and usually require a single authoritative database.
A UUID is a 128-bit identifier designed to be unique without a central authority. The version matters more than most people realize: some versions are random, while others embed a timestamp and a machine or node identifier. What a UUID does not guarantee is that it is unguessable or that it is short. For a database key, a UUID is a reliable way to avoid collisions. For a security token, you want a cryptographically random version and enough entropy that guessing is infeasible — a plain counter is not the same thing.
UUIDs have a real storage and indexing cost. They are not sequential, so they fragment indexes and take more space than an auto-incrementing integer. The benefit is that they can be generated offline, merged from multiple sources without collision, and reused without revealing how many rows exist. If your system will grow across multiple servers or need to merge data, a UUID is a strong choice. If it is a simple single table, the extra cost may not be worth it — reach for the tool that fits the actual need.
The two versions you will most often pick between are v4 and v7. Version 4 is a purely random 122-bit value; version 7 embeds a timestamp, which makes keys roughly time-ordered and friendlier to indexes. For general-purpose identifiers, a random v4 is the safe default. For a high-volume system where index performance matters, a time-ordered version is worth considering. Whatever you choose, generate the ID once and store it consistently — mixing versions across a single dataset only adds confusion.