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)

019a97d8-ce06-7b40-9d8a-a65cdd5dc7e9
019a97d8-ce06-7ccd-a613-f45ed4332db4
019a97d8-ce06-7e0d-8783-c81e1860b9df
019a97d8-ce06-7f30-8c87-6f2a90a0fae6
019a97d8-ce07-704a-9956-63aa585e76e9
019a97d8-ce07-7165-be19-95283eac0e06
019a97d8-ce07-727f-8a0a-786522eb2586
019a97d8-ce07-7396-b125-39a680b84eb8
019a97d8-ce07-74b5-b3c2-835d0a3f1a20
019a97d8-ce07-75cf-a044-a8944b13b055
019a97d8-ce07-76ea-9702-9609e9c1e58a
019a97d8-ce07-7805-9808-2b34e6993a3c
019a97d8-ce07-791b-99f1-1b7678d2937c
019a97d8-ce07-7a36-8b6c-4ccc5407db7f
019a97d8-ce07-7b50-81d9-76b4250584e1

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)

1f0c49d9-8715-60ce-a936-4cf95d479851
1f0c49d9-8715-6254-a936-4cf95d479851
1f0c49d9-8715-633a-a936-4cf95d479851
1f0c49d9-8715-6402-a936-4cf95d479851
1f0c49d9-8715-64ca-a936-4cf95d479851
1f0c49d9-8715-6592-a936-4cf95d479851
1f0c49d9-8715-6650-a936-4cf95d479851
1f0c49d9-8715-670e-a936-4cf95d479851
1f0c49d9-8715-67d6-a936-4cf95d479851
1f0c49d9-8715-6894-a936-4cf95d479851
1f0c49d9-8715-69d4-a936-4cf95d479851
1f0c49d9-8715-6a92-a936-4cf95d479851
1f0c49d9-8715-6b5a-a936-4cf95d479851
1f0c49d9-8715-6c18-a936-4cf95d479851
1f0c49d9-8715-6cd6-a936-4cf95d479851

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)

473adda6-9a84-4e6a-b431-4469c8d7004c
11e52432-939a-4c09-b025-1712ff145197
8c3f902f-5db3-4836-8caf-5c6594e48363
a139d1c6-e1a4-42a7-b3a3-25ef349bc859
a9b979fe-80f8-44a6-ba04-40e48df6fed4
244bcfce-034f-4764-9137-d88c0943cdb1
3293fb42-e99c-4869-bbe2-ec6174254278
2aff5dbe-df8d-4050-ae96-30af548253ad
c41d71ca-9360-4ed9-a7bb-b23965496b3f
a5a6cd8a-e75c-4d3e-9cee-ca89f930bf5d
ab2f56b0-cb81-4909-b6df-5edc1aae6198
53a7c992-f55e-487f-8036-7e4db76f46e3
974f9f3c-b3ab-40de-86d5-311e43547ec0
3a338fde-e142-445d-97d2-fbf8c591b465
7dbf8c10-a70c-4981-8be2-cd2ecb3af6c8

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)

987161ea-c49d-11f0-a936-4cf95d479851
9871624e-c49d-11f0-a936-4cf95d479851
987162b2-c49d-11f0-a936-4cf95d479851
98716316-c49d-11f0-a936-4cf95d479851
98716370-c49d-11f0-a936-4cf95d479851
987163d4-c49d-11f0-a936-4cf95d479851
98716438-c49d-11f0-a936-4cf95d479851
987164a6-c49d-11f0-a936-4cf95d479851
9871650a-c49d-11f0-a936-4cf95d479851
98716564-c49d-11f0-a936-4cf95d479851
987165be-c49d-11f0-a936-4cf95d479851
98716622-c49d-11f0-a936-4cf95d479851
9871667c-c49d-11f0-a936-4cf95d479851
987166e0-c49d-11f0-a936-4cf95d479851
98716744-c49d-11f0-a936-4cf95d479851

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)

97ea7f27-eb03-8214-87e9-5ce32bd83b97
939c8027-eb03-8214-87e9-5ce32bd83b97
0e128127-eb03-8214-87e9-5ce32bd83b97
d9f98227-eb03-8214-87e9-5ce32bd83b97
c1d28327-eb03-8214-87e9-5ce32bd83b97
edac8427-eb03-8214-87e9-5ce32bd83b97
670b8527-eb03-8214-87e9-5ce32bd83b97
ffd68627-eb03-8214-87e9-5ce32bd83b97
9c3f8727-eb03-8214-87e9-5ce32bd83b97
7e528827-eb03-8214-87e9-5ce32bd83b97
fd348927-eb03-8214-87e9-5ce32bd83b97
07fb8a27-eb03-8214-87e9-5ce32bd83b97
62168b27-eb03-8214-87e9-5ce32bd83b97
58758c27-eb03-8214-87e9-5ce32bd83b97
d73e8d27-eb03-8214-87e9-5ce32bd83b97

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

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: