UUID Generator & Inspector
Generate UUID v4 and v7 identifiers in bulk — random and time-ordered. Inspect any UUID to extract its embedded creation timestamp and version details. Also generates GUIDs for Microsoft conventions.
About this tool
The Universally Unique Identifier (UUID) is the standard way to label records, sessions, files, and events so that two systems can refer to the same thing without colliding. A UUID v4 packs 122 bits of cryptographically random data into a 36-character string like 550e8400-e29b-41d4-a716-446655440000 — the safest default, and natively supported by crypto.randomUUID() in every modern browser. UUID v7 replaces the random front with a millisecond Unix timestamp, so IDs created in sequence sort chronologically — ideal for database primary keys and event logs.
The GUID tab wraps the same 128-bit value in curly braces to match Microsoft conventions. The Short UUID tab compresses the 128 bits into 22 URL-safe characters (no ambiguous 0/O/1/l). The tool also generates NanoID and ULID for users who need those formats, but for a dedicated multi-format generator with CUID2, KSUID, and Snowflake decoding, see the Multi-Format ID Generator.
Switch to the Inspect tab, paste any UUID (v1, v4, v7), ULID, or NanoID, and the tool detects the kind, reformats it to canonical form, and — for time-embedded identifiers — recovers the exact millisecond it was created.
FAQ
Which UUID version should I use? ›
UUID v4 is the safest default — purely random, no timestamp, and supported natively by crypto.randomUUID() in every modern browser. Choose UUID v7 when you need IDs that sort by creation time (for database primary keys and chronological event logs). Use GUID when integrating with Microsoft tooling.
Are these UUIDs unique? ›
Yes, with overwhelming probability. A v4 UUID has 122 bits of entropy — the chance of a collision among 100 million IDs is roughly one in a billion. UUID v7 keeps 74 bits of randomness after the timestamp prefix, which is still far beyond what a single application will ever exhaust.
What is the difference between UUID and GUID? ›
Nothing practical. GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit standard. This tool wraps GUIDs in curly braces to match the Microsoft convention. Any system that accepts UUIDs also accepts the underlying bytes of a GUID.
Why does UUID v7 sort chronologically? ›
The first 48 bits of a v7 UUID hold the Unix timestamp in milliseconds. Because the most significant bits come first, a byte-wise string comparison of two v7 UUIDs puts the earlier one first — the same ordering a B-tree database index uses.