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)

019cd695-2c89-7629-b72c-e3c55904a472
019cd695-2c89-77b7-9255-a49de20d29dd
019cd695-2c89-78f6-a3b2-e6d4525ebc01
019cd695-2c89-7a15-aa87-544d2f21a1a6
019cd695-2c89-7b30-adc9-b1ff1572223d
019cd695-2c89-7c46-94e6-aac58e4d22f9
019cd695-2c89-7d5d-8ca5-df19e74cf482
019cd695-2c89-7e77-9bef-1f7dba316a25
019cd695-2c89-7f8e-b57d-db0a7b4944db
019cd695-2c8a-70a8-a1ef-542d7eea74c2
019cd695-2c8a-71c3-9573-5307d42b4336
019cd695-2c8a-72da-bd26-510afaff14fd
019cd695-2c8a-73f0-8745-e43518f32f0d
019cd695-2c8a-7507-8a2f-1c8ce81814a1
019cd695-2c8a-761d-a732-ec75d62ec7d5

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)

1f11c503-69d2-6160-84e5-4cf95d479851
1f11c503-69d2-62f0-84e5-4cf95d479851
1f11c503-69d2-63d6-84e5-4cf95d479851
1f11c503-69d2-64a8-84e5-4cf95d479851
1f11c503-69d2-6570-84e5-4cf95d479851
1f11c503-69d2-6638-84e5-4cf95d479851
1f11c503-69d2-6700-84e5-4cf95d479851
1f11c503-69d2-67d2-84e5-4cf95d479851
1f11c503-69d2-689a-84e5-4cf95d479851
1f11c503-69d2-6962-84e5-4cf95d479851
1f11c503-69d2-6aa2-84e5-4cf95d479851
1f11c503-69d2-6b6a-84e5-4cf95d479851
1f11c503-69d2-6c28-84e5-4cf95d479851
1f11c503-69d2-6cf0-84e5-4cf95d479851
1f11c503-69d2-6db8-84e5-4cf95d479851

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)

340a9889-a2f7-44be-baed-49986ae383ae
2d0727c4-f734-492c-a415-73fcd96c4e7e
3e083160-0dfc-4080-8a87-5fa0d7db81a8
8d8d8158-e884-4810-a790-16164ab5fec5
4d8c352d-68d8-4c7d-a6c0-7409c0ec1450
a81e972d-43db-4b0f-88ff-862d5644359d
26c6e031-dbcd-4b6c-aa29-3a60ea7ce8fc
6e0f283a-5047-420f-97a1-62d371a6ceb1
8e2d6f17-803f-4c5d-bb0d-7c093f214ee8
769ef7e9-2eaf-4d2c-9327-443664d860f2
664100aa-1e3c-4c02-91d8-0634333bec7e
605c071c-ac3e-4b88-b8a3-e7d84dad4161
3150277a-8b4e-4846-bb28-d85042a0ea17
8c49555f-be47-4e2e-b541-871e21a9d9c0
5fd7a126-944c-4088-b55e-aeab96892972

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)

369d3380-1c50-11f1-84e5-4cf95d479851
369d33ee-1c50-11f1-84e5-4cf95d479851
369d3452-1c50-11f1-84e5-4cf95d479851
369d34ac-1c50-11f1-84e5-4cf95d479851
369d3510-1c50-11f1-84e5-4cf95d479851
369d356a-1c50-11f1-84e5-4cf95d479851
369d35ce-1c50-11f1-84e5-4cf95d479851
369d3632-1c50-11f1-84e5-4cf95d479851
369d3696-1c50-11f1-84e5-4cf95d479851
369d36fa-1c50-11f1-84e5-4cf95d479851
369d375e-1c50-11f1-84e5-4cf95d479851
369d37cc-1c50-11f1-84e5-4cf95d479851
369d3830-1c50-11f1-84e5-4cf95d479851
369d3894-1c50-11f1-84e5-4cf95d479851
369d38f8-1c50-11f1-84e5-4cf95d479851

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)

6083711a-af01-8504-87ea-5ce32bd83b97
3800721a-af01-8504-87ea-5ce32bd83b97
db6f731a-af01-8504-87ea-5ce32bd83b97
9160741a-af01-8504-87ea-5ce32bd83b97
111a751a-af01-8504-87ea-5ce32bd83b97
7a25761a-af01-8504-87ea-5ce32bd83b97
836a771a-af01-8504-87ea-5ce32bd83b97
9975781a-af01-8504-87ea-5ce32bd83b97
fc8f791a-af01-8504-87ea-5ce32bd83b97
106b7a1a-af01-8504-87ea-5ce32bd83b97
68677b1a-af01-8504-87ea-5ce32bd83b97
ad097c1a-af01-8504-87ea-5ce32bd83b97
43967e1a-af01-8504-87ea-5ce32bd83b97
cc2f7f1a-af01-8504-87ea-5ce32bd83b97
4dfb801a-af01-8504-87ea-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: