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)

019f00f9-cb2c-7246-bb0f-f7b251f36e26
019f00f9-cb2c-7425-b783-b1a2ff1a9cc4
019f00f9-cb2c-7565-bbcd-01ee310fcff5
019f00f9-cb2c-7684-ac2c-2b91489e7b27
019f00f9-cb2c-779a-85fe-fd840730dda1
019f00f9-cb2c-78b1-8823-b8250bfbc483
019f00f9-cb2c-79c7-a346-3c5f4cd8afad
019f00f9-cb2c-7ade-a638-f15a209a9d55
019f00f9-cb2c-7bf4-bda3-2dfa8423ab8b
019f00f9-cb2c-7d0b-9076-6f44729564a8
019f00f9-cb2c-7e1d-bf82-7a95d0e8b438
019f00f9-cb2c-7f34-b467-fb44feb080d1
019f00f9-cb2d-7046-86ec-c1b301e3e855
019f00f9-cb2d-7161-b5d7-9dcdd7a7e525
019f00f9-cb2d-7277-87fd-9109cf3b7fcf

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)

1f170e83-111d-69b0-820e-4cf95d479851
1f170e83-111d-6b54-820e-4cf95d479851
1f170e83-111d-6c3a-820e-4cf95d479851
1f170e83-111d-6d02-820e-4cf95d479851
1f170e83-111d-6dd4-820e-4cf95d479851
1f170e83-111d-6e92-820e-4cf95d479851
1f170e83-111d-6f50-820e-4cf95d479851
1f170e83-111e-6018-820e-4cf95d479851
1f170e83-111e-60d6-820e-4cf95d479851
1f170e83-111e-619e-820e-4cf95d479851
1f170e83-111e-62de-820e-4cf95d479851
1f170e83-111e-63b0-820e-4cf95d479851
1f170e83-111e-6478-820e-4cf95d479851
1f170e83-111e-6536-820e-4cf95d479851
1f170e83-111e-65f4-820e-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)

3111e6c6-70e8-11f1-820e-4cf95d479851
3111e72a-70e8-11f1-820e-4cf95d479851
3111e798-70e8-11f1-820e-4cf95d479851
3111e7fc-70e8-11f1-820e-4cf95d479851
3111e860-70e8-11f1-820e-4cf95d479851
3111e8c4-70e8-11f1-820e-4cf95d479851
3111e928-70e8-11f1-820e-4cf95d479851
3111e98c-70e8-11f1-820e-4cf95d479851
3111e9f0-70e8-11f1-820e-4cf95d479851
3111ea54-70e8-11f1-820e-4cf95d479851
3111eab8-70e8-11f1-820e-4cf95d479851
3111eb26-70e8-11f1-820e-4cf95d479851
3111eb8a-70e8-11f1-820e-4cf95d479851
3111ebf8-70e8-11f1-820e-4cf95d479851
3111ec66-70e8-11f1-820e-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)

57e8513a-5a05-800b-87ea-5ce32bd83b97
720b523a-5a05-800b-87ea-5ce32bd83b97
42ed533a-5a05-800b-87ea-5ce32bd83b97
1b6a543a-5a05-800b-87ea-5ce32bd83b97
c0a0553a-5a05-800b-87ea-5ce32bd83b97
7319563a-5a05-800b-87ea-5ce32bd83b97
010c573a-5a05-800b-87ea-5ce32bd83b97
5800583a-5a05-800b-87ea-5ce32bd83b97
65f2593a-5a05-800b-87ea-5ce32bd83b97
08625a3a-5a05-800b-87ea-5ce32bd83b97
28bb5b3a-5a05-800b-87ea-5ce32bd83b97
b2125c3a-5a05-800b-87ea-5ce32bd83b97
63685d3a-5a05-800b-87ea-5ce32bd83b97
1b745e3a-5a05-800b-87ea-5ce32bd83b97
5e7f5f3a-5a05-800b-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)

050fd4c2-2a83-4fee-b0e4-a1095bae1589
55b519a8-9f54-42c0-85ac-4eee0cb3791a
015721f7-8f4e-4569-a124-c3e6c00ebde3
44ec4d3b-a87c-432d-992b-0a7801dd6d59
b90fc7c5-b5e4-4fc4-8f7f-b07869a81b35
535818a2-8db5-4319-bb6b-8b343f0fb74b
040f9a88-1ab1-4bf6-bd54-2b434567de49
0481a4b0-1b8e-4f7f-b88f-50f0e44e4eea
48cafc90-3311-470c-9839-07bda8e483ca
fedda447-671b-4c0f-8bb6-ec855ec29aa8
6f2e21e3-652b-40b8-b640-82d77638fc73
400101ab-7043-4235-b6e1-3dff0df2d299
59c97543-d248-4016-b39c-b4f1bbb804be
7622c55c-818f-4372-b3de-a8a90c1a14f6
207c955e-272a-4219-a712-3257f12328b7

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: