Generate UUIDs
Get random version 4 UUIDs for database keys, test data or file names. Make one or a thousand, format them the way your system expects and copy or download the list.
- Free
- Runs in your browser
- Up to 1,000 at once
- No sign-up
How It Works
Get UUIDs in three steps.
Choose how many
From 1 to 1,000.
Pick the format
Upper or lower case, with or without hyphens, optionally in braces.
Copy or download
Copy the list or save it as uuids.txt. Press Generate for a fresh set.
What is a version 4 UUID?
A UUID (universally unique identifier, called a GUID in Microsoft tools) is a 128-bit value written as 32 hex digits in five groups, such as 3f2b8c1e-9d4a-4f6b-8e2a-7c5d9b1a0e34. In version 4, 122 of those bits are random. The chance of two random UUIDs ever colliding is so small that systems can create IDs independently, on different servers or offline, without checking a central list.
Random UUIDs make poor clustered primary keys in some databases because new rows land in random places in the index. If insert speed matters, look at time-ordered UUIDs (version 7) instead.
Secure randomness
Uses crypto.randomUUID, your browser's cryptographically secure generator, not Math.random.
Version and variant bits
The 13th digit is always 4 and the 17th is 8, 9, a or b, as the standard (RFC 9562) requires.
GUID formatting
Upper case and braces give the {XXXXXXXX-…} style used in Windows and .NET.
Bulk output
Up to 1,000 per batch, one per line.
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Why Use This UUID Generator
Standard UUIDs, formatted your way.
Cryptographically random
Generated with the browser's secure random source.
Bulk generation
A thousand UUIDs in one click for test data or seeding.
Formatting options
Case, hyphens and braces to match any system.
Download as text
Save the list as a .txt file, one UUID per line.
Frequently Asked Questions
Questions people ask about the UUID Generator.
In theory yes, in practice no. With 122 random bits you would need to generate about a billion UUIDs every second for around 85 years to have a 50% chance of a single duplicate.
None in practice. GUID is Microsoft's name for the same 128-bit identifier. GUIDs are often written in upper case and wrapped in braces, which you can switch on here.
No. They are created in your browser and only exist on this page until you copy them or close it.
Version 4 is fully random and reveals nothing about the machine or time it was made on, which makes it the most widely used. Version 1 includes a timestamp and a node ID; version 7 starts with a timestamp so IDs sort by creation time.
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