Generate random v4 or time-ordered v7 UUIDs. Runs on your device.
A version 4 UUID is 122 random bits and nothing else. It suits a value that only has to be unique, such as a database row key or a test fixture. A version 7 UUID starts with the current time in milliseconds, then random bits. Because the time comes first, v7 IDs sort in the order they were made, which keeps a database index tidy when rows are added one after another. The same time is also visible to anyone who reads the ID, so a v7 ID shows when it was made. Pick v7 when order matters, and v4 when it does not. The random bits come from your browser. A version 7 batch picks one random start and adds one for each further ID, so every ID in the batch shares the same millisecond.
A UUID has 32 hexadecimal digits in five groups, written 8-4-4-4-12 with hyphens. The first digit of the third group is the version: 4 for random and 7 for time-ordered. The first digit of the fourth group is the variant. A standard UUID has a variant digit of 8, 9, a or b, which is what this tool makes. Any other digit there means the ID follows an older or different layout. The Check a UUID field reads these two digits from a UUID you paste and tells you what they mean. For a version 7 UUID that uses the standard variant, it also gives the time the ID was made, in UTC.
The three format options change how the same IDs are written. Uppercase turns 550e8400-e29b-41d4-a716-446655440000 into 550E8400-E29B-41D4-A716-446655440000. No hyphens removes the four hyphens, leaving 32 digits. Braces wrap the ID in curly brackets, which is how many Windows and .NET tools print a GUID, for example {550E8400-E29B-41D4-A716-446655440000}. Changing a format option does not make new IDs. The same list is shown in the new style, so you can switch styles and still copy the IDs you already have. Check your system's format before you paste: a database column may accept only one of these styles.
Each UUID is made by your browser's own cryptographic random number generator, in this tab. The UUID values are never sent anywhere or saved. Close the tab and the list is gone. The only things kept are the version, count and format options, in this browser's local storage. The page counts visits with Google Analytics. Its events carry only the tool's name, the copy or download action, and the fact that a result appeared, never an ID or the check text. A UUID is an identifier, not a secret. Do not use one as a password, an API key or a login token. For a password, use the Password Generator on this site.
No, and no generator can promise it. A version 4 UUID has 122 random bits, so two of them matching is extremely unlikely, but this tool does not check a list against earlier IDs. Within one batch of 1,000, the chance of a repeat is negligible, and the tests check that 10,000 generated IDs were all different.
GUID is the name Microsoft tools often use for the same 128-bit identifier. The format is the same, and the usual GUID style is uppercase with braces, such as {550E8400-E29B-41D4-A716-446655440000}. Use the Uppercase and Braces options to match a system that expects that style.
All IDs in one batch share the millisecond the batch was made. The tool starts from a random value and adds one for each new ID, so 1,000 IDs in a batch sort in the order they appear, and they share the same first 12 hex digits. Each new batch starts from a new random value and a new time.
Not here. The limit is 1,000 UUIDs per run. The list shows the first 100, and Copy all or Download .txt holds every ID in the run. For 10,000, run the tool ten times with a count of 1,000, or use a script.
Paste it into the Check a UUID field. It reads the version digit, which is the first digit of the third group, and the variant digit, which is the first digit of the fourth group. For example, 018bcfe5-6800-77ee-9dcc-bbaa99887766 reports version 7 and a time of 2023-11-14T22:13:20.000Z.
No. A UUID is an identifier, and a version 7 UUID shows when it was made. Do not use one as a password, an API key or a session token. Use the Password Generator, which makes a random password of 8 to 64 characters, for anything that must stay secret.