Generate UUIDs instantly — v4, v7 or v1
The UUID generator creates universally unique identifiers for database keys, API resources, file names, test data and anything else that needs an ID nobody else will ever pick. Choose the version, how many you need (up to 1,000 at once) and the format, and copy the list straight into your code, spreadsheet or SQL script.
Most people want version 4, the random UUID. For database primary keys, version 7 is often the better choice: it starts with a millisecond timestamp, so new IDs sort in creation order and keep B-tree indexes compact. Version 1 is included for legacy systems. Every UUID follows RFC 9562, the 2024 standard that replaced RFC 4122.
IDs are generated with your browser’s cryptographically secure random number generator (crypto.getRandomValues and crypto.randomUUID). Nothing is sent to or logged on a server. The built-in inspector also tells you the version, variant and creation time hidden inside any UUID you paste.
How to use the UUID Generator
- Pick a UUID version: 4 for random IDs, 7 for time-ordered IDs, 1 for legacy systems, or the special Nil and Max values.
- Enter How many you need, from 1 to 1,000. The list regenerates automatically.
- Choose Output as — one per line, a comma-separated or quoted list, an SQL
IN-style list, or a JSON array — and tick uppercase, no hyphens or braces if your system needs them. - Press Copy all or Download .txt.
- To check an existing ID, paste it into Validate or inspect a UUID to see whether it is valid, which version it is and, for v1, v6 and v7, when it was created.
UUID Generator features
Cryptographically secure
Random bits come from the Web Crypto API, the same source browsers use for encryption keys — never from Math.random().
Correct UUID v7
A 48-bit Unix millisecond timestamp, version and variant bits per RFC 9562, and a counter so IDs generated in the same millisecond still sort in order.
Bulk output in useful formats
Generate up to 1,000 at once as lines, comma lists, quoted lists, SQL lists or JSON — with uppercase, hyphen-free or {braced} GUID styles.
UUID inspector
Validates any UUID and decodes its version, variant, clock sequence, node and embedded timestamp, with the exact RFC 9562 test vectors passing.
Private v1 node IDs
Version 1 UUIDs use a random node ID with the multicast bit set, as RFC 9562 recommends, instead of exposing a real MAC address.
UUID versions compared
| Version | Built from | Sortable by time | Best for |
|---|---|---|---|
| v4 | 122 random bits | No | General-purpose IDs, tokens, public identifiers |
| v7 | 48-bit Unix ms timestamp + 74 random bits | Yes | Database primary keys, event IDs, logs |
| v1 | 60-bit timestamp (100 ns since 1582) + clock sequence + node | Not as text | Legacy systems that expect v1 |
| v6 | v1 fields reordered so text sorts by time | Yes | Migrating v1 systems (decoded by the inspector) |
| v3 / v5 | MD5 / SHA-1 hash of a namespace and name | No | Repeatable IDs for the same input |
| Nil / Max | All zeros / all ones | — | Placeholders and sentinels |
How unique is a UUID?
A version 4 UUID has 122 random bits, which gives 2122 ≈ 5.3 × 1036 possible values. By the birthday bound, you would need to generate about 2.7 × 1018 of them before the chance of a single duplicate reached 50% — that is a billion per second for about 85 years. In practice, a duplicate is far more likely to come from a bug, such as a badly seeded random generator, than from chance.
Version 7 trades some randomness for order: each millisecond has 74 random bits plus a counter, which is still far more than enough to avoid collisions across many servers.
UUIDs are identifiers, not secrets. Do not use them as passwords or session tokens on their own; use the Password Generator for secrets, and the Unix Timestamp Converter to work with the times decoded here.
UUID Generator FAQ
What is the difference between a UUID and a GUID?
They are the same thing. GUID (globally unique identifier) is Microsoft’s name for a UUID. GUIDs are often written in uppercase and wrapped in braces, like {3F2504E0-4F89-41D3-9A0C-0305E82C3301} — tick Uppercase and Wrap in braces to get that style.
Should I use UUID v4 or v7 for database keys?
Use v7 when IDs are primary keys in a B-tree index, such as PostgreSQL or MySQL. Because v7 values increase over time, new rows are inserted at the end of the index instead of at random places, which reduces page splits and keeps inserts fast. Use v4 when you do not want IDs to reveal when they were created.
Can a UUID v7 reveal when it was created?
Yes. The first 48 bits are a Unix timestamp in milliseconds, so anyone can read the creation time — paste one into the inspector to see it. Avoid v7 for IDs that are public and time-sensitive.
Are the UUIDs generated here truly unique?
They are random or time-based exactly as the standard specifies, using a cryptographically secure generator, so the chance of a collision is negligible. This UUID generator does not keep a list of IDs; no tool can guarantee global uniqueness, but the probability of a clash is effectively zero.
Is it safe to use these UUIDs in production?
Yes. They are generated locally in your browser with the Web Crypto API and are never transmitted or stored, so no one else has seen them.
How do I generate a UUID in code?
In JavaScript use crypto.randomUUID(); in Python uuid.uuid4(); in PostgreSQL gen_random_uuid(); in Java UUID.randomUUID(). Native v7 support is newer, arriving in recent versions of PostgreSQL and other platforms — check your version’s documentation.