UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019fb24e-0aeb-757d-b6ff-8bdae28fdfb8
019fb24e-0aeb-7740-a130-b09093f5d71d
019fb24e-0aeb-787f-b0b9-e09e5f0b7505
019fb24e-0aeb-799a-8225-943c7ab1ef5d
019fb24e-0aeb-7ab5-8546-6e2ef44448a0
019fb24e-0aeb-7bc7-b2a4-104b1f8d2ffb
019fb24e-0aeb-7cda-bd39-31b265dc7e5d
019fb24e-0aeb-7dec-ac38-69bd205eb45f
019fb24e-0aeb-7efe-b7ad-5834c2284ffe
019fb24e-0aec-700d-9816-e6c1267f3a54
019fb24e-0aec-7123-8b44-75316dfab5d3
019fb24e-0aec-7232-84e7-634cabdc64c8
019fb24e-0aec-7344-8214-3c52528c2b76
019fb24e-0aec-7457-930c-d67da8d772fd
019fb24e-0aec-7569-b4be-6ce38dc926e6

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)

1f18bf71-c0bf-6418-889f-4cf95d479851
1f18bf71-c0bf-65ee-889f-4cf95d479851
1f18bf71-c0bf-66de-889f-4cf95d479851
1f18bf71-c0bf-67a6-889f-4cf95d479851
1f18bf71-c0bf-6878-889f-4cf95d479851
1f18bf71-c0bf-6940-889f-4cf95d479851
1f18bf71-c0bf-69fe-889f-4cf95d479851
1f18bf71-c0bf-6ac6-889f-4cf95d479851
1f18bf71-c0bf-6b84-889f-4cf95d479851
1f18bf71-c0bf-6c4c-889f-4cf95d479851
1f18bf71-c0bf-6db4-889f-4cf95d479851
1f18bf71-c0bf-6e90-889f-4cf95d479851
1f18bf71-c0bf-6f58-889f-4cf95d479851
1f18bf71-c0c0-6020-889f-4cf95d479851
1f18bf71-c0c0-60e8-889f-4cf95d479851

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)

1c0c01c4-8bf7-11f1-889f-4cf95d479851
1c0c0228-8bf7-11f1-889f-4cf95d479851
1c0c028c-8bf7-11f1-889f-4cf95d479851
1c0c02f0-8bf7-11f1-889f-4cf95d479851
1c0c0354-8bf7-11f1-889f-4cf95d479851
1c0c03ae-8bf7-11f1-889f-4cf95d479851
1c0c0412-8bf7-11f1-889f-4cf95d479851
1c0c0476-8bf7-11f1-889f-4cf95d479851
1c0c04e4-8bf7-11f1-889f-4cf95d479851
1c0c0548-8bf7-11f1-889f-4cf95d479851
1c0c05ac-8bf7-11f1-889f-4cf95d479851
1c0c061a-8bf7-11f1-889f-4cf95d479851
1c0c067e-8bf7-11f1-889f-4cf95d479851
1c0c06e2-8bf7-11f1-889f-4cf95d479851
1c0c0750-8bf7-11f1-889f-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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

b8aae42e-2b02-830d-87ea-5ce32bd83b97
efb6e52e-2b02-830d-87ea-5ce32bd83b97
09ebe62e-2b02-830d-87ea-5ce32bd83b97
1e44e72e-2b02-830d-87ea-5ce32bd83b97
d21fe82e-2b02-830d-87ea-5ce32bd83b97
64b3e92e-2b02-830d-87ea-5ce32bd83b97
86ceea2e-2b02-830d-87ea-5ce32bd83b97
33c3eb2e-2b02-830d-87ea-5ce32bd83b97
500aec2e-2b02-830d-87ea-5ce32bd83b97
2913ed2e-2b02-830d-87ea-5ce32bd83b97
e3c6ee2e-2b02-830d-87ea-5ce32bd83b97
f52cef2e-2b02-830d-87ea-5ce32bd83b97
7ceaf02e-2b02-830d-87ea-5ce32bd83b97
539df12e-2b02-830d-87ea-5ce32bd83b97
29cef22e-2b02-830d-87ea-5ce32bd83b97

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)

03b5fba2-ad18-4317-aa57-9a1adb5bef85
f6207a5e-257c-4602-991f-436605412404
de282398-f6aa-4736-9135-da773fd06185
199cb381-a98c-4de6-a925-917ee652a67e
f8afc7fb-a1a3-47c9-b3e7-840b32d8cce9
d723b9a8-9e9f-4aaa-a21e-01fbe1d1e6b6
c82893aa-b5ff-40b3-b388-da3a768a1f21
bbd4e3dd-f218-4162-8b46-919405af0101
aad8936f-76f8-4653-a41e-5c96c7908875
4193d8ec-f041-4779-8d80-5ec9cbacae03
ad6b5fc1-d741-4256-a7d7-b26587994692
c50e9ed9-d7fb-45c2-986d-f70bbe17a248
380779fc-6269-4e6e-968b-a67a9a92e04d
02a1a9f2-94bb-4943-8ac6-2379c7a3cf81
5bfe5407-512d-4735-b934-9664fc65aec9

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: