UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate random and/or time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate random (version 4) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate other UUID types
  • NCS (variant 0) UUID
  • Generate DCE Security (version 2) UUID
  • Generate name-based (version 3 / 5 / New: 8) UUID
  • New: Generate Custom (version 8) UUID
• Interpret a UUID
• Interpret a MAC address (MAC / EUI / ELI / SAI / AAI)
  • Generate an AAI

Generate random and/or time-based UUIDs

New: Generate Unix Epoch time-based (version 7) UUID ⭐

A UUIDv7 measures time in the Unix Epoch with an accuracy between 1ms and 245ns, depending on how many bits are spent for the timestamp (48-60 bits). The rest of the UUID (62-74 bits) is filled with random data. The timestamp is at the front of the UUID, therefore the UUIDs are monotonically increasing, which is good for using them in database indexes. Since this UUID version does not contain a MAC address, it is also recommended due to the improved privacy.

Show format

Variant 1, Version 7 UUID:
- 48 bit Unix Time in milliseconds
-  4 bit Version (fix 0x7)
- 12 bit Data
-  2 bit Variant (fix 0b10)
- 62 bit Data

Structure of data (74 bits):
- OPTIONAL : Sub-millisecond timestamp fraction (0-12 bits)
- OPTIONAL : Carefully seeded counter
- Random generated bits for any remaining space

Time resolution for various sub-millisecond bits:
0 bits fraction = 1 ms
1 bits fraction = 500 µs
2 bits fraction = 250 µs
3 bits fraction = 125 µs
4 bits fraction = 62.5 µs
5 bits fraction = 31.25 µs
6 bits fraction = 15.625 µs
7 bits fraction = 7.8125 µs
8 bits fraction = 3.90625 µs
9 bits fraction = 1.953125 µs
10 bits fraction = 976.5625 ns
11 bits fraction = 488.28125 ns
12 bits fraction = 244.140625 ns

This implementation outputs:
- 12 bits sub-millisecond timestamp (~245ns resolution)
- no counter
- 62 bits random data

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

018f763f-2ddb-71cf-b264-2796d26b6c25
018f763f-2ddb-7361-a1c8-fd8ab9acbe37
018f763f-2ddb-74a8-8d1d-7f520a041913
018f763f-2ddb-75cf-ad52-36c532cd4810
018f763f-2ddb-76ee-91c2-26332df2ba11
018f763f-2ddb-780d-8cea-3ee0967f32bf
018f763f-2ddb-792c-998d-808ef3fca8db
018f763f-2ddb-7a4a-b8ba-8b1d69a15c15
018f763f-2ddb-7b69-a957-06d2053c687f
018f763f-2ddb-7c8c-95e7-743c54db3c5e
018f763f-2ddb-7e05-a2b6-17b424b92e19
018f763f-2ddb-7f59-9f15-e3df61401ce9
018f763f-2ddc-707f-9cb4-f7c29f6a407b
018f763f-2ddc-71a2-af37-266d9db35dfc
018f763f-2ddc-72c1-a012-394c9cc31773

New: Generate reordered Gregorian time-based (version 6) UUID ⏰

Like UUIDv1, this kind of UUID is made of the MAC address of the generating computer, the time, and a clock sequence. However, the components in UUIDv6 are reordered (time is at the beginning), so that UUIDs are monotonically increasing, which is good for using them in database indexes.

Show format

Variant 1, Version 6 UUID:
- 48 bit High Time
-  4 bit Version (fix 0x6)
- 12 bit Low Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence High
-  8 bit Clock Sequence Low
- 48 bit MAC Address

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

1ef11cd1-770a-6d64-a02a-4cf95d479851
1ef11cd1-770a-6f44-a02a-4cf95d479851
1ef11cd1-770b-602a-a02a-4cf95d479851
1ef11cd1-770b-60fc-a02a-4cf95d479851
1ef11cd1-770b-61c4-a02a-4cf95d479851
1ef11cd1-770b-628c-a02a-4cf95d479851
1ef11cd1-770b-634a-a02a-4cf95d479851
1ef11cd1-770b-6412-a02a-4cf95d479851
1ef11cd1-770b-64d0-a02a-4cf95d479851
1ef11cd1-770b-6598-a02a-4cf95d479851
1ef11cd1-770b-66ec-a02a-4cf95d479851
1ef11cd1-770b-67be-a02a-4cf95d479851
1ef11cd1-770b-687c-a02a-4cf95d479851
1ef11cd1-770b-6944-a02a-4cf95d479851
1ef11cd1-770b-6a02-a02a-4cf95d479851

Generate random (version 4) UUID 🎲

A UUIDv4 is made of 122 random bits. No other information is encoded in this kind of UUID.

Show format

Variant 1, Version 4 UUID:
- 48 bit Random High
-  4 bit Version (fix 0x4)
- 12 bit Random Mid
-  2 bit Variant (fix 0b10)
- 62 bit Random Low

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

307d859b-8441-43d2-9b40-8826a3bc6a69
52232f9e-faf3-4870-acbd-3904c3399c40
857e8676-bef0-4186-b86f-f27d227a4e91
02ac2f8a-26b9-4e4c-9bcd-82c3a430b8da
65d369f1-880f-49fa-bf8e-26db2c528265
565a3ed9-8109-4d20-b542-11984ddde101
f929da75-d339-494c-9cd7-05a962b9121c
b5889b88-e064-45c6-bdeb-505cfb79eb59
bd7fb8e4-3d32-43d0-a6dc-9f144134a768
44d945f2-e256-432d-b044-1f083fce292d
ba3268cc-6a96-4467-b416-c4db5eccf93e
0bd97446-b296-4f67-9dbd-794af5edb1db
1d2c4eda-5ed3-46ad-98c6-4a30f8e25a5e
a6c0bbd1-59f2-467a-80d6-4252eb0147e6
d007f216-3bce-4425-8eb7-70eca27a35e9

Generate Gregorian time-based (version 1) UUID ⏰

A UUIDv1 is made of the MAC address of the generating computer, the time, and a clock sequence.

Show format

Variant 1, Version 1 UUID:
- 32 bit Low Time
- 16 bit Mid Time
-  4 bit Version (fix 0x1)
- 12 bit High Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence High
-  8 bit Clock Sequence Low
- 48 bit MAC Address

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

1770bf70-11cd-11ef-a02a-4cf95d479851
1770bfde-11cd-11ef-a02a-4cf95d479851
1770c042-11cd-11ef-a02a-4cf95d479851
1770c09c-11cd-11ef-a02a-4cf95d479851
1770c100-11cd-11ef-a02a-4cf95d479851
1770c164-11cd-11ef-a02a-4cf95d479851
1770c1c8-11cd-11ef-a02a-4cf95d479851
1770c222-11cd-11ef-a02a-4cf95d479851
1770c286-11cd-11ef-a02a-4cf95d479851
1770c2e0-11cd-11ef-a02a-4cf95d479851
1770c344-11cd-11ef-a02a-4cf95d479851
1770c39e-11cd-11ef-a02a-4cf95d479851
1770c40c-11cd-11ef-a02a-4cf95d479851
1770c466-11cd-11ef-a02a-4cf95d479851
1770c4d4-11cd-11ef-a02a-4cf95d479851

Generate SQL Server sortable time-based (version 8) UUID

The sorting of UUIDs in SQL Server is rather confusing and incompatible with UUIDv6 and UUIDv7.
Therefore this method developed by HickelSOFT generates UUIDs which are sortable by SQL Server.
They have a time resolution of 1 milliseconds combined with 16 bits of random data.
C# implementation | PHP implementation

Show format

Version 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 16 bit Random data
-  8 bit UTC Milliseconds transformed from 1000ms to 0..255, deviation -2ms..2ms (hex encoded)
-  8 bit UTC Seconds (hex encoded)
- 16 bit UTC Minute of the day (1..1440, hex encoded)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 48 bit Signature 0x5ce32bd83b96

Version 1: Resolution of 1 milliseconds, random part of 16 bits, local timezone, 48 zero bits "signature", NOT UUIDv8 conform:
- 16 bit Random data
-  8 bit Generator's local timezone Milliseconds transformed from 1000ms to 0..255, deviation -4ms..0ms (hex encoded)
-  8 bit Generator's local timezone Seconds (BCD encoded)
-  8 bit Generator's local timezone Minute (BCD encoded)
-  8 bit Generator's local timezone Hour (BCD encoded)
-  8 bit Generator's local timezone Day (BCD encoded)
-  8 bit Generator's local timezone Month (BCD encoded)
-  8 bit Generator's local timezone 2-digit year (BCD encoded)
-  8 bit Generator's local timezone 2-digit century (BCD encoded)
- 48 bit Signature 0x000000000000

Here are 15 UUIDs that were created just for you! (Reload the page to get more)

7dd21a2b-0205-8087-87e8-5ce32bd83b96
da421b2b-0205-8087-87e8-5ce32bd83b96
ff351c2b-0205-8087-87e8-5ce32bd83b96
c7101d2b-0205-8087-87e8-5ce32bd83b96
25e81e2b-0205-8087-87e8-5ce32bd83b96
e6f91f2b-0205-8087-87e8-5ce32bd83b96
3b07202b-0205-8087-87e8-5ce32bd83b96
d4fc212b-0205-8087-87e8-5ce32bd83b96
bac9222b-0205-8087-87e8-5ce32bd83b96
c301232b-0205-8087-87e8-5ce32bd83b96
e8d8242b-0205-8087-87e8-5ce32bd83b96
8339252b-0205-8087-87e8-5ce32bd83b96
1c2b262b-0205-8087-87e8-5ce32bd83b96
a421272b-0205-8087-87e8-5ce32bd83b96
9040282b-0205-8087-87e8-5ce32bd83b96

Generate other UUID types

The following types of UUIDs are less common and/or require special knowledge. Please only use the following generators if you know what you are doing.

NCS (variant 0) UUID

The NCS UUIDs are a legacy format initially designed by Apollo Computer that cannot be generated anymore, because the amount of available timestamp bits was exhausted on 5 September 2015. As an example, here is the last possible NCS UUID (all bits of the timestamp are set to 1) for IP address 127.0.0.1: ffffffff-ffff-0000-027f-000001000000.

Show format

Variant 0 UUID:
- 32 bit High Time
- 16 bit Low Time
- 16 bit Reserved
-  1 bit Variant (fix 0b0)
-  7 bit Family
- 56 bit Node

Generate DCE Security (version 2) UUID

An UUIDv2 contains information about the creator (person, group, or organization), the generating system (MAC address), and time. The creator information replaced parts of the time bits, therefore the time resolution is very low.

Show format

Variant 1, Version 2 UUID:
- 32 bit Local Domain Number
- 16 bit Mid Time
-  4 bit Version (fix 0x2)
- 12 bit High Time
-  2 bit Variant (fix 0b10)
-  6 bit Clock Sequence
-  8 bit Local Domain
- 48 bit MAC Address

Generate name-based (version 3 / 5 / New: 8) UUID

An UUIDv3 is made out of a MD5 hash and an UUIDv5 is made out of a SHA1 hash. RFC 9562 also contains an example for a custom UUIDv8 implementation that uses modern hash algorithms.

Show format

Variant 1, Version 3/5/8 UUID:
- 48 bit Hash High
-  4 bit Version (fix 0x3, 0x5, or 0x8)
- 12 bit Hash Mid
-  2 bit Variant (fix 0b10)
- 62 bit Hash Low


As shown in RFC 9562 Appendix B.2:
UUIDv8(HashAlgo, NameSpaceUuid, Data) := ConvertRawBytesToUuid_v8(HashAlgo( Binary[NameSpaceUuid] || Data )).

New: Generate Custom (version 8) UUID

UUIDv8 is made of 122 bits application-specific / custom data. The other 6 bits are used to specify the variant and version of the UUID, to make it RFC-compatible.

Show format

Variant 1, Version 8 UUID:
- 48 bit Custom data [Block 1+2]
-  4 bit Version (fix 0x8)
- 12 bit Custom data [Block 3]
-  2 bit Variant (fix 0b10)
- 62 bit Custom data [Block 4+5]

Interpret a UUID

You can enter a UUID in the following notations:

• Classic notation (case insensitive, curly braces optional): 9e83839a-5967-11e4-8c1c-78e3b5fc7f22
• As OID: 2.25.210700883446948645633376489934419689250

The script will output:

• Notation as UUID and OID
• Version, variant, and additional data (date and time, clock sequence, node id, etc.)

Please enter a UUID or UUID OID:

Interpret a MAC address (MAC / EUI / ELI / SAI / AAI)

You can enter a UUID in the following notations:

• AA-BB-CC-DD-EE-FF
• AA:BB:CC:DD:EE:FF
• AABBCC.DDEEFF (case insensitive)
• AA-BB-CC-DD-EE-FF-11-22 (EUI-64)
• AA:BB:CC:DD:EE:FF-11-22 (EUI-64)
• fe80::1322:33ff:fe44:5566 (IPv6 Link Local / EUI-64)

The script will output:

• Information about the I/G and U/L flags.
• Information about the entry in the IEEE registry, if available.
• Information about the registrant, if available.

Please enter a MAC (EUI, ELI, SAI, AAI), or IPv6-Link-Local address:

Generate an AAI

An Administratively Assigned Identifier (AAI) is a MAC address which can be locally defined by applications or an administrator. Unlike the EUI, an AAI is NOT worldwide unique.

The following options are rather unusual, but are implemented for the sake of completeness: