Free UUID/GUID generator: create v1, v4, v5, v7 UUIDs plus ULID and NanoID in bulk, copy or export — or decode a UUID to read its version and timestamp.
Random UUID — the default choice for most uses.
You might also find these calculators useful
Create universally unique identifiers in one click — UUID v4 (random), v7 (time-ordered), v1, namespace-based v3/v5, plus Nil/Max, ULID, and NanoID. Generate in bulk, copy or export, and decode any UUID to read its version and timestamp. RFC 9562-compliant, crypto-secure, and 100% in your browser.
A UUID (universally unique identifier) is a 128-bit value, written as 32 hexadecimal digits in five groups (8-4-4-4-12). A GUID is the Microsoft term for the same thing. Different versions are generated differently: v4 is fully random; v7 embeds a millisecond timestamp so IDs sort by creation time (ideal for database keys); v1 combines a timestamp with a node value; v3 and v5 derive a deterministic ID by hashing a namespace plus a name (MD5 for v3, SHA-1 for v5). ULID and NanoID are popular non-UUID alternatives — ULID is time-sortable, NanoID is short and URL-safe.
Structure
v7 gives time-sortable primary keys that index efficiently.
v4 for request IDs, object keys, and filenames.
v5 to derive a stable ID from a name, such as a URL.
Bulk-generate IDs to seed databases and fixtures.
NanoID or ULID for compact, URL-friendly identifiers.
Get collision-resistant identifiers for database rows, API keys, files, and events.
Pick v4 for general use, v7 for sortable database keys, or v5 for deterministic IDs.
Generate up to 1,000 at once and export them to seed databases or tests.
Decode an unknown UUID to see its version, variant, and embedded timestamp.
RFC 9562-compliant, crypto-secure randomness, generated entirely in your browser.
v4 is fully random. v7 puts a millisecond timestamp at the start, so v7 IDs sort by creation time — which makes them far better as database primary keys because they keep the index ordered. Both are 128-bit and effectively unique.
Use v4 for general-purpose unique IDs. Use v7 for database primary keys (time-sortable). Use v5 when you need a deterministic ID from a namespace and name. v1 is mostly legacy; v3 is like v5 but uses the weaker MD5 hash.
It is astronomically unlikely. A v4 UUID has 122 random bits — you would need to generate billions per second for many years to have a meaningful chance of a collision.
Yes. This tool uses a cryptographically secure random source (Web Crypto), not Math.random, so the IDs are unpredictable.
GUID (globally unique identifier) is the Microsoft term for a UUID. They are the same 128-bit format; GUIDs are often shown uppercase and in braces.
ULID is a 26-character, time-sortable identifier using Crockford base32. NanoID is a short, URL-safe random ID (21 characters by default). Both are popular alternatives to UUIDs.