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)

019b1e02-290a-7836-bf14-6b8320d576a2
019b1e02-290a-79d3-9b5f-fd3719cf06fb
019b1e02-290a-7b17-af34-4ff25298459e
019b1e02-290a-7c3a-a802-f2e1fa23f3b2
019b1e02-290a-7d54-bb0c-a2b8ab831be7
019b1e02-290a-7e6f-a8de-13c0d13f5a5e
019b1e02-290a-7f86-a8d7-93facab4f8a6
019b1e02-290b-70a0-9ae3-6bceb5d5cede
019b1e02-290b-71b7-b214-278fe6e4ada8
019b1e02-290b-72d1-9e93-cd66363d4b10
019b1e02-290b-73e8-a01a-1dd030ba4faf
019b1e02-290b-74fe-a2bb-f62cc25f5fbe
019b1e02-290b-7619-b3fb-32c260e35a4a
019b1e02-290b-7734-9656-d85ee1e1e28b
019b1e02-290b-784a-9a90-8a6e4add3e93

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)

1f0d9164-7e49-6610-aff6-4cf95d479851
1f0d9164-7e49-67aa-aff6-4cf95d479851
1f0d9164-7e49-689a-aff6-4cf95d479851
1f0d9164-7e49-696c-aff6-4cf95d479851
1f0d9164-7e49-6a34-aff6-4cf95d479851
1f0d9164-7e49-6afc-aff6-4cf95d479851
1f0d9164-7e49-6bc4-aff6-4cf95d479851
1f0d9164-7e49-6c8c-aff6-4cf95d479851
1f0d9164-7e49-6d4a-aff6-4cf95d479851
1f0d9164-7e49-6e12-aff6-4cf95d479851
1f0d9164-7e49-6f52-aff6-4cf95d479851
1f0d9164-7e4a-6024-aff6-4cf95d479851
1f0d9164-7e4a-60e2-aff6-4cf95d479851
1f0d9164-7e4a-61aa-aff6-4cf95d479851
1f0d9164-7e4a-6268-aff6-4cf95d479851

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)

0f58f379-3bf5-4620-88cf-39903ff4ee44
75dfe372-c06b-432f-83c4-48718ba151b2
1732e8f9-820d-4322-881d-09a17ad9eff8
1aca16bf-dfc6-409a-a868-7bb85b544886
08939b07-ec3e-4f76-a11e-183336b54a4d
e113d975-7782-49d9-93f1-6c3b8f9c6b60
70a4b4fd-8d60-40b2-9f92-55e15158346e
1ba64b29-c273-4f4f-919a-8b1271799bb2
13b8939f-1428-47d9-b04b-33daa8d1e892
74d6b07d-752c-4cc6-a923-8d67d3655f6b
ff64abc1-fd9f-45e7-8a8c-cad22183a7fb
cfab61bc-0b66-49b0-bb71-386d6d9c2b0d
f1bfbf5c-8925-4e3d-97b9-57cdb72f8f91
a943a400-11c7-4dcb-b5c8-6928b623f0c6
9de2dae9-c1e6-4ba2-8ebc-bf83c26919c4

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)

47e4a84e-d916-11f0-aff6-4cf95d479851
47e4a8bc-d916-11f0-aff6-4cf95d479851
47e4a920-d916-11f0-aff6-4cf95d479851
47e4a984-d916-11f0-aff6-4cf95d479851
47e4a9de-d916-11f0-aff6-4cf95d479851
47e4aa4c-d916-11f0-aff6-4cf95d479851
47e4aab0-d916-11f0-aff6-4cf95d479851
47e4ab0a-d916-11f0-aff6-4cf95d479851
47e4ab78-d916-11f0-aff6-4cf95d479851
47e4abdc-d916-11f0-aff6-4cf95d479851
47e4ac40-d916-11f0-aff6-4cf95d479851
47e4ac9a-d916-11f0-aff6-4cf95d479851
47e4acfe-d916-11f0-aff6-4cf95d479851
47e4ad62-d916-11f0-aff6-4cf95d479851
47e4adbc-d916-11f0-aff6-4cf95d479851

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)

4742b738-3504-8c15-87e9-5ce32bd83b97
5357b838-3504-8c15-87e9-5ce32bd83b97
b112b938-3504-8c15-87e9-5ce32bd83b97
3438ba38-3504-8c15-87e9-5ce32bd83b97
41abbb38-3504-8c15-87e9-5ce32bd83b97
1872bc38-3504-8c15-87e9-5ce32bd83b97
20abbd38-3504-8c15-87e9-5ce32bd83b97
922abe38-3504-8c15-87e9-5ce32bd83b97
f7debf38-3504-8c15-87e9-5ce32bd83b97
bb7ec038-3504-8c15-87e9-5ce32bd83b97
5c1dc138-3504-8c15-87e9-5ce32bd83b97
79f8c238-3504-8c15-87e9-5ce32bd83b97
37fec338-3504-8c15-87e9-5ce32bd83b97
897ec438-3504-8c15-87e9-5ce32bd83b97
c834c538-3504-8c15-87e9-5ce32bd83b97

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: