Paste a UUID (or GUID) to check whether it is valid and see what is inside: version, variant, the creation time hidden in v1, v6 and v7 UUIDs, the clock sequence and the node or MAC address. Switch to bulk mode to validate a whole list at once.
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Input
Status
Version
Timestamp (UTC)
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How to use the UUID Decoder & Validator
Paste a UUID into the box. Hyphens, braces and the urn:uuid: prefix are all accepted, in any letter case.
Read the verdict: the badge says whether the value is a valid RFC 9562 UUID and which version it is.
Check the fields: the color-coded layout shows where the timestamp, version, variant, clock sequence and node live.
See the creation time for time-based UUIDs (v1, v6, v7) in UTC and in your local time.
Validate a list: open the Bulk tab, paste one UUID per line and click Check UUIDs, then copy the valid ones or download a CSV report.
UUID layout by version
Every UUID is 128 bits shown as 32 hexadecimal digits in five groups: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx. M is the version digit and the top bits of N are the variant. For RFC 9562 UUIDs N is always 8, 9, a or b.
Version
Contents
Timestamp
Example
1
60-bit Gregorian time, 14-bit clock sequence, 48-bit node (MAC)
Yes, 100 ns since 1582-10-15
6ba7b810-9dad-11d1-80b4-00c04fd430c8
2
DCE Security: like v1 but with a local user/group ID
Partial (about 7 minutes)
rarely used
3
MD5 hash of namespace + name
No
6fa459ea-ee8a-3ca4-894e-db77e160355e
4
122 random bits
No
9b2f6c1e-4a7d-4e3b-8c5f-2d1a0b9e7f63
5
SHA-1 hash of namespace + name
No
2ed6657d-e927-568b-95e1-2665a8aea6a2
6
v1 fields reordered so the value sorts by time
Yes, 100 ns since 1582-10-15
1ec9414c-232a-6b00-b3c8-9f6bdeced846
7
48-bit Unix milliseconds + 74 random bits
Yes, Unix ms
017f22e2-79b0-7cc3-98c4-dc0c0c07398f
8
Custom, vendor-defined layout
Application-specific
n/a
How the timestamps are decoded
Version 1: the timestamp is split into three fields. Rebuild it as time_hi (the 3 hex digits after the version digit) + time_mid (group 2) + time_low (group 1). For 6ba7b810-9dad-11d1-… that is 1d19dad6ba7b810 hex, a count of 100-nanosecond ticks since 15 October 1582. Subtract 122,192,928,000,000,000 (the ticks between 1582 and 1970) and divide by 10,000 to get Unix milliseconds: 4 February 1998, 22:13:53.151 UTC.
Version 6 stores the same 60-bit value with the most significant bits first, so you read groups 1 and 2 followed by the three digits after the version. Version 7 is simplest: the first 12 hex digits are Unix time in milliseconds, so 017f22e279b0 = 1,645,557,742,000 ms = 22 February 2022, 19:22:22 UTC.
Validation regular expression
To accept any RFC 9562 UUID (versions 1-8, correct variant) in code, a common pattern is:
Add an alternative for 00000000-0000-0000-0000-000000000000 and ffffffff-ffff-ffff-ffff-ffffffffffff if the Nil and Max UUIDs should pass too. A purely syntactic check such as ^[0-9a-f]{8}(-[0-9a-f]{4}){3}-[0-9a-f]{12}$ also accepts legacy GUIDs with other variants, which this tool reports as "well-formed but not RFC 9562".
Frequently asked questions
How do I know which version a UUID is?
Look at the first hex digit of the third group. In 6ba7b810-9dad-11d1-80b4-00c04fd430c8 the third group is 11d1, so it is a version 1 UUID. A random UUID such as 3f2b8c1e-5a7d-4e3b-9c5f-2d1a0b9e7f63 has a 4 there. The tool reads this automatically.
What makes a UUID valid?
A UUID is 128 bits written as 32 hexadecimal digits, normally in 8-4-4-4-12 groups. To follow RFC 9562 (formerly RFC 4122) the variant bits must be 10 (the first digit of the fourth group is 8, 9, a or b) and the version digit must be 1 to 8. The Nil UUID (all zeros) and Max UUID (all f) are also defined by the standard.
Can I get the creation date from a UUID?
Only for time-based versions. Version 1 and 6 store a 60-bit count of 100-nanosecond intervals since 15 October 1582, and version 7 stores Unix time in milliseconds in its first 48 bits. Versions 3, 4, 5 and 8 contain no standard timestamp.
Does a version 1 UUID reveal my MAC address?
It can. The last 12 hex digits of a v1 UUID are the node field, which older generators filled with the network card's MAC address. Modern libraries often use a random node instead and set the multicast bit to mark it as not a real address; the tool tells you which case applies.
What is the difference between a UUID and a GUID?
GUID is Microsoft's name for the same 128-bit identifier. They share the text format and are interchangeable. Some old Microsoft GUIDs use the reserved Microsoft variant (fourth group starting with c or d), which the decoder labels separately.
Is it safe to paste UUIDs here?
Yes. The decoding runs entirely in JavaScript in your browser. Nothing is sent to a server, so you can check production identifiers without exposing them.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.