UUID Generator — v1, v4, v7
Generate UUID v1 (time-based), v4 (random), or v7 (Unix-ms sortable) — up to 100 at once. All generation happens entirely in your browser. Nothing is sent to any server.
v4Random — cryptographically secure random bits. The most widely used UUID version.
1 UUID generated
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information in computer systems. It is standardized by RFC 4122 (and the newer RFC 9562) and appears in the format xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx, where M is the version and N is the variant.
UUID Versions Supported
- v1 — Time-based: Encodes the current timestamp (100-nanosecond intervals since the Gregorian epoch) plus a random node ID. Preserves generation order but embeds timing information — avoid when privacy matters.
- v4 — Random: 122 bits of cryptographically secure randomness. No ordering guarantees. The most widely-used UUID version — suitable for session tokens, object IDs, and most general-purpose uses.
- v7 — Unix-ms Sortable (RFC 9562): Encodes a Unix millisecond timestamp in the leading 48 bits, followed by random bits. Monotonically increasing within the same millisecond. Ideal for database primary keys because it maintains insertion order and avoids B-tree fragmentation.
v4 vs v7 — Which Should I Use?
| Property | UUID v4 | UUID v7 |
|---|---|---|
| Sortable | No | Yes (ms precision) |
| DB index friendly | Poor (random scatters) | Excellent (ordered) |
| Contains timestamp | No | Yes (leading 48 bits) |
| Randomness | 122 bits | 74 bits |
| RFC | RFC 4122 | RFC 9562 (2024) |
| Best for | Tokens, secrets, general IDs | DB PKs, event IDs, logs |
How to Use
- Select V1, V4, or V7 from the version tabs.
- Choose lowercase or UPPERCASE output format.
- Set the count (1–100) for bulk generation.
- Click Generate — hover any row to copy individually, or use Copy All.
Frequently Asked Questions
Is a UUID the same as a GUID?
Yes. GUID (Globally Unique Identifier) is Microsoft's term for the same concept. They follow the same format and are interchangeable.
How unique is a UUID v4?
With 122 random bits, the probability of a collision is approximately 1 in 5.3 × 10³⁶ — negligible for all practical purposes.
Is UUID v7 supported everywhere?
UUID v7 is defined in RFC 9562 (April 2024). Library support is growing rapidly (e.g. Python 3.13+, PostgreSQL 17+). For databases that don't natively support it yet, v7 values can be stored as a standard UUID column.