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)

019bcaf9-4d04-757d-8e01-071f402de8a5
019bcaf9-4d04-770b-9f97-85f9956855cf
019bcaf9-4d04-785f-acb8-27cfad16058d
019bcaf9-4d04-7986-907f-b23a2453ada8
019bcaf9-4d04-7aa8-827c-224a3b4dfd19
019bcaf9-4d04-7bc7-a76c-9379ff8e37c8
019bcaf9-4d04-7cea-820a-59edc10e80d1
019bcaf9-4d04-7e09-97b3-c7c04bbdd715
019bcaf9-4d04-7f27-8f71-3eaaf7d53465
019bcaf9-4d05-7046-a739-ba18a5452d3f
019bcaf9-4d05-7113-9696-6dc185584ed1
019bcaf9-4d05-723e-9481-1956626629fa
019bcaf9-4d05-735d-9842-bc2916fb38b1
019bcaf9-4d05-747f-83c9-0f5a2667cd9c
019bcaf9-4d05-759e-bc1b-7c101ee16637

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)

1f0f37ab-dd1e-64da-bade-4cf95d479851
1f0f37ab-dd1e-6674-bade-4cf95d479851
1f0f37ab-dd1e-6764-bade-4cf95d479851
1f0f37ab-dd1e-682c-bade-4cf95d479851
1f0f37ab-dd1e-68f4-bade-4cf95d479851
1f0f37ab-dd1e-69bc-bade-4cf95d479851
1f0f37ab-dd1e-6a7a-bade-4cf95d479851
1f0f37ab-dd1e-6b42-bade-4cf95d479851
1f0f37ab-dd1e-6c00-bade-4cf95d479851
1f0f37ab-dd1e-6cc8-bade-4cf95d479851
1f0f37ab-dd1e-6e3a-bade-4cf95d479851
1f0f37ab-dd1e-6f02-bade-4cf95d479851
1f0f37ab-dd1e-6fc0-bade-4cf95d479851
1f0f37ab-dd1f-6074-bade-4cf95d479851
1f0f37ab-dd1f-613c-bade-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)

ba665ce5-48df-4bcb-bfd0-6bc7e1d9cd39
3a7e97d3-827c-4299-9742-2f1f935b8e16
9ae1b6c3-5833-43ac-b21f-cf482c93a2b7
df7815e3-2da1-4c1d-b06c-1bce06b1bd89
c72a993d-b0ec-45cc-8b8c-b2ab3eedf465
fc5ce50d-ec0a-4fc3-a0d4-57237fcf5518
64ca560a-0fb1-4335-bcde-84624d2eb379
8c17cb66-b5af-415d-910b-41ab273e0766
dd48e1ee-1a0c-4b17-90de-950b12d4123a
75215ed0-3295-466c-b782-87c10f5b18a2
deae45ca-e2d3-4e03-9e55-bfd6e0b9ffac
c9c48d78-ea8a-476a-85f9-604ab313f3af
43a05ba3-46e8-41f5-8ccf-e53a22c7ae71
6d0647bc-7585-4555-9500-ccd23531cc37
aace864f-77af-43ab-9b12-bc5e6a53479e

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)

bdd1f650-f37a-11f0-bade-4cf95d479851
bdd1f6be-f37a-11f0-bade-4cf95d479851
bdd1f722-f37a-11f0-bade-4cf95d479851
bdd1f786-f37a-11f0-bade-4cf95d479851
bdd1f7ea-f37a-11f0-bade-4cf95d479851
bdd1f844-f37a-11f0-bade-4cf95d479851
bdd1f8b2-f37a-11f0-bade-4cf95d479851
bdd1f920-f37a-11f0-bade-4cf95d479851
bdd1f984-f37a-11f0-bade-4cf95d479851
bdd1f9de-f37a-11f0-bade-4cf95d479851
bdd1fa42-f37a-11f0-bade-4cf95d479851
bdd1fa9c-f37a-11f0-bade-4cf95d479851
bdd1fb00-f37a-11f0-bade-4cf95d479851
bdd1fb6e-f37a-11f0-bade-4cf95d479851
bdd1fbc8-f37a-11f0-bade-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 3: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 compliant:
- 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) LITTLE ENDIAN (CD AB = 0xABCD)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded) LITTLE ENDIAN (8C AB = 0xABC)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded)
- 48 bit Signature 0x5ce32bd83b97

Version 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 compliant:
- 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) BIG ENDIAN (AB CD = 0xABCD) = WRONG!!!
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded) BIG ENDIAN (8A BC = 0xABC) = WRONG!!!
-  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 compliant:
- 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)

b3437822-e201-8101-87ea-5ce32bd83b97
d00e7922-e201-8101-87ea-5ce32bd83b97
44037a22-e201-8101-87ea-5ce32bd83b97
2f2e7b22-e201-8101-87ea-5ce32bd83b97
65627c22-e201-8101-87ea-5ce32bd83b97
86287d22-e201-8101-87ea-5ce32bd83b97
7e857e22-e201-8101-87ea-5ce32bd83b97
fb9f7f22-e201-8101-87ea-5ce32bd83b97
38478022-e201-8101-87ea-5ce32bd83b97
7af68122-e201-8101-87ea-5ce32bd83b97
94788222-e201-8101-87ea-5ce32bd83b97
bcf98322-e201-8101-87ea-5ce32bd83b97
204f8422-e201-8101-87ea-5ce32bd83b97
87e58522-e201-8101-87ea-5ce32bd83b97
30d98722-e201-8101-87ea-5ce32bd83b97

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

A 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

A UUIDv3 is made out of a MD5 hash and a 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: