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)

019c5c64-a304-7969-8b55-83bfc399215e
019c5c64-a304-7b2c-a740-7cbb52eeb4e0
019c5c64-a304-7c73-9e99-11ff9890e2aa
019c5c64-a304-7d96-99cb-b0ed63854897
019c5c64-a304-7eb5-92e1-802c4314594f
019c5c64-a304-7fd3-b552-193b71537097
019c5c64-a305-70ee-a31a-31cf559c7d88
019c5c64-a305-720d-ac61-ca7aaf4b841d
019c5c64-a305-732c-b181-01f41c9c225b
019c5c64-a305-7446-bd64-a93b0663da06
019c5c64-a305-7561-8ea5-f7017f234a0c
019c5c64-a305-767f-a0e8-da3a91471b50
019c5c64-a305-779e-b90e-95c7584c1b9b
019c5c64-a305-78c1-9b75-359fd830606f
019c5c64-a305-79dc-8306-7c8a1ea9198d

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)

1f109ab2-ea14-6f5c-ad4a-4cf95d479851
1f109ab2-ea15-611e-ad4a-4cf95d479851
1f109ab2-ea15-620e-ad4a-4cf95d479851
1f109ab2-ea15-62e0-ad4a-4cf95d479851
1f109ab2-ea15-63b2-ad4a-4cf95d479851
1f109ab2-ea15-647a-ad4a-4cf95d479851
1f109ab2-ea15-6542-ad4a-4cf95d479851
1f109ab2-ea15-6614-ad4a-4cf95d479851
1f109ab2-ea15-66d2-ad4a-4cf95d479851
1f109ab2-ea15-679a-ad4a-4cf95d479851
1f109ab2-ea15-6902-ad4a-4cf95d479851
1f109ab2-ea15-69de-ad4a-4cf95d479851
1f109ab2-ea15-6ab0-ad4a-4cf95d479851
1f109ab2-ea15-6b82-ad4a-4cf95d479851
1f109ab2-ea15-6c4a-ad4a-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)

8f8cfbde-915e-426f-81ae-2b9f0c89bb85
aedee17a-9d06-4608-9fbc-78ee340091cb
80d5276b-a974-4759-8861-34d0eeec0192
c694a674-b88d-4a13-9009-c6243fc65e19
ae06bb73-2624-4d10-a4e9-edc6f18737c8
441f542c-5d00-4764-b18b-20df839a07f4
34d8cc74-9376-49dc-9755-8fa317487cb4
9d63f0cd-24e7-45ab-bd56-d9d0a4142875
b10c741e-2dc7-4e02-8325-75d948ce6359
60cf0bca-41cc-4998-8e17-b6fdef2c48bf
14526278-ec2e-418f-84a9-a4276f206097
132b2c76-e884-4c7a-8b5b-b77a42a6b1fb
9da3afc6-597c-4723-975a-479c3df45a9c
648c96b4-b830-4f5c-96de-2a6d521ca152
404bf223-9cc8-48a2-9c2b-6ece5ef22bbe

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)

2ea1617c-09ab-11f1-ad4a-4cf95d479851
2ea161ea-09ab-11f1-ad4a-4cf95d479851
2ea1624e-09ab-11f1-ad4a-4cf95d479851
2ea162b2-09ab-11f1-ad4a-4cf95d479851
2ea16316-09ab-11f1-ad4a-4cf95d479851
2ea1637a-09ab-11f1-ad4a-4cf95d479851
2ea163de-09ab-11f1-ad4a-4cf95d479851
2ea16442-09ab-11f1-ad4a-4cf95d479851
2ea164a6-09ab-11f1-ad4a-4cf95d479851
2ea1650a-09ab-11f1-ad4a-4cf95d479851
2ea1656e-09ab-11f1-ad4a-4cf95d479851
2ea165dc-09ab-11f1-ad4a-4cf95d479851
2ea1664a-09ab-11f1-ad4a-4cf95d479851
2ea166ae-09ab-11f1-ad4a-4cf95d479851
2ea16726-09ab-11f1-ad4a-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)

988e282d-3803-8d02-87ea-5ce32bd83b97
0e0c292d-3803-8d02-87ea-5ce32bd83b97
96032a2d-3803-8d02-87ea-5ce32bd83b97
0b342b2d-3803-8d02-87ea-5ce32bd83b97
37f42c2d-3803-8d02-87ea-5ce32bd83b97
7c972d2d-3803-8d02-87ea-5ce32bd83b97
6b822e2d-3803-8d02-87ea-5ce32bd83b97
e4c12f2d-3803-8d02-87ea-5ce32bd83b97
fb16312d-3803-8d02-87ea-5ce32bd83b97
09ed322d-3803-8d02-87ea-5ce32bd83b97
ffb8332d-3803-8d02-87ea-5ce32bd83b97
1cbd342d-3803-8d02-87ea-5ce32bd83b97
3f21352d-3803-8d02-87ea-5ce32bd83b97
2d6e362d-3803-8d02-87ea-5ce32bd83b97
e0f9372d-3803-8d02-87ea-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: