UUID Generator
Generate UUID v4, v7, and v1-style identifiers in your browser using the Web Crypto API. Bulk-generate up to 1000 UUIDs, copy to clipboard, or download.
0
Generated
v4
Version
100%
Unique
122 bits of cryptographic randomness. Most widely used. Suitable for database primary keys, session IDs, and correlation IDs.
Millisecond-precision Unix timestamp in the high bits + random suffix. Monotonically sortable. Ideal for indexed database keys.
100-ns Gregorian timestamp (since Oct 1582) + random node. Structurally valid v1 format with a random node ID for privacy.
UUID Structure
Disclaimer: Free tool provided “as is” by MonitorGiant. No warranty or liability for any data loss, security issues, or infrastructure problems arising from use of this tool. Results are for informational purposes only. · A Free Tool by MonitorGiant
What is UUID Generator?
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in computer systems without a central authority. This tool generates UUID v4 (random), UUID v7 (time-ordered random, ideal for databases), and UUID v1-style (time-based) identifiers using your browser's Web Crypto API. Because the random component has 122 bits of entropy in v4, the probability of generating a duplicate UUID across all systems ever is astronomically small.
How to use this tool
- 1 Select your UUID version: v4 for general use, v7 for database primary keys (sorts chronologically), or v1-style for time-based identifiers.
- 2 Set the quantity — generate 1 or bulk-generate up to 1000 UUIDs at once.
- 3 Choose your preferred format: standard (with hyphens), uppercase, or no hyphens.
- 4 Click 'Generate' to create the UUIDs instantly.
- 5 Use 'Copy all' to copy the full list to your clipboard, or 'Download' to save as a .txt file.
When would you use this?
- Assigning primary keys to database rows where you need IDs to be unique across distributed systems without a central counter.
- Generating correlation IDs for tracing requests across microservices — a UUID in every log line makes it easy to follow a request end to end.
- Creating unique filenames for uploaded assets, avoiding collisions when multiple users upload files simultaneously.
Frequently asked questions — UUID Generator
What is a UUID v4?
A UUID v4 (Universally Unique Identifier version 4) is a 128-bit random identifier formatted as 32 hexadecimal digits in the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. The '4' in the third group identifies the version, and the 'y' position encodes the variant. 122 of the 128 bits are random, giving approximately 5.3 × 10^36 possible values — making collisions astronomically unlikely even when generating billions of UUIDs.
What is the difference between UUID v4 and v7?
UUID v4 is entirely random, which means UUIDs generated in sequence are not sortable — they appear in arbitrary order in a database index, causing fragmentation and slower inserts. UUID v7 combines a 48-bit Unix millisecond timestamp with random bits, making it both unique and lexicographically sortable by creation time. This makes v7 significantly better as a database primary key because rows can be inserted in timestamp order, keeping the index compact and query-efficient.
Are UUIDs truly unique?
In practice, yes. The probability of generating two identical UUID v4s is approximately 1 in 5.3 × 10^36. To put that in perspective: generating 1 billion UUIDs per second for the entire age of the universe would still give you less than a 0.000000001% chance of a collision. For UUID v7, the timestamp prefix further reduces collision probability within the same millisecond window. UUIDs are safe to use as unique identifiers in distributed systems without a central registry.
How UUID Generator works
- 1
Choose version
- 2
Set quantity & format
- 3
Copy or download
All UUIDs are generated locally using window.crypto. Nothing is sent to any server.
Searching for a free UUID generator online? UUIDs (Universally Unique Identifiers) are 128-bit values used as database primary keys, session tokens, correlation IDs, and file names. UUID v4 is fully random — ideal when you need collision-resistant IDs without a central authority. UUID v7 encodes a sortable millisecond timestamp in the first 48 bits, making it better for database indexing with no full-table scans. This tool uses the browser's Web Crypto API — the same randomness source used by operating systems and password managers — to guarantee true cryptographic randomness.
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