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)

019dd72b-a639-72f2-a9ce-af118b698f41
019dd72b-a639-74cd-a50f-383a24649898
019dd72b-a639-7636-88c3-e4e2d8b82bd2
019dd72b-a639-7775-a74a-2fa845fba851
019dd72b-a639-78b5-aa77-dd6de85ba104
019dd72b-a639-79f8-ba90-b415a820f4f6
019dd72b-a639-7b3c-b4d5-e2868e2cd904
019dd72b-a639-7c77-ae0f-d79110813d6d
019dd72b-a639-7daf-8e7b-4b7ae2708df5
019dd72b-a639-7eee-9d78-76f3e2a21001
019dd72b-a63a-7025-a0ba-87f1fa66ce1e
019dd72b-a63a-7165-ab89-50f162db32bb
019dd72b-a63a-72a4-a057-b1f8935c1b1a
019dd72b-a63a-73e0-a429-d2d452662146
019dd72b-a63a-751f-9450-3fd026d3a36c

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)

1f143772-c8e8-6ada-90bd-4cf95d479851
1f143772-c8e8-6d28-90bd-4cf95d479851
1f143772-c8e8-6e86-90bd-4cf95d479851
1f143772-c8e8-6fd0-90bd-4cf95d479851
1f143772-c8e9-6110-90bd-4cf95d479851
1f143772-c8e9-6250-90bd-4cf95d479851
1f143772-c8e9-6390-90bd-4cf95d479851
1f143772-c8e9-6520-90bd-4cf95d479851
1f143772-c8e9-66a6-90bd-4cf95d479851
1f143772-c8e9-682c-90bd-4cf95d479851
1f143772-c8e9-6a34-90bd-4cf95d479851
1f143772-c8e9-6b92-90bd-4cf95d479851
1f143772-c8e9-6cdc-90bd-4cf95d479851
1f143772-c8e9-6e1c-90bd-4cf95d479851
1f143772-c8e9-6f66-90bd-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)

eaa751a0-3545-4a0a-8796-11a56c7dd23d
0885fa47-0163-4373-848f-b07030261d2b
1967c36b-ccfc-400d-9658-b14f50062ae3
e59c1a9c-8895-407d-96b5-12a0c5980826
e24d805c-93c1-4070-9f8a-7fdb3c78e384
fdeb15f3-3c6b-46f2-ae63-5637c3c9fe8f
79d13a8e-445d-4a75-91d6-088e30047a8b
c9b2a4a7-2055-4068-816f-b400037f2dae
bd0d7576-5a84-48e7-9a34-c4316745def7
eec6596a-d921-4e8c-a4f3-2430f0eca409
5f7ecda6-74a7-4b31-9ab1-6d212de3810c
6a56d3b7-4da5-4e09-8cb9-4a35366dbdb1
eef5c891-783a-4426-8a65-fd61146ec916
05555d48-6054-4d1a-9f5e-3a2f57434271
bfc4f5d3-0854-4e87-9304-6c0b2879080e

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)

2c8ea682-4377-11f1-90bd-4cf95d479851
2c8ea722-4377-11f1-90bd-4cf95d479851
2c8ea7a4-4377-11f1-90bd-4cf95d479851
2c8ea844-4377-11f1-90bd-4cf95d479851
2c8ea8ee-4377-11f1-90bd-4cf95d479851
2c8ea98e-4377-11f1-90bd-4cf95d479851
2c8eaa24-4377-11f1-90bd-4cf95d479851
2c8eaac4-4377-11f1-90bd-4cf95d479851
2c8eab5a-4377-11f1-90bd-4cf95d479851
2c8eabfa-4377-11f1-90bd-4cf95d479851
2c8eac90-4377-11f1-90bd-4cf95d479851
2c8ead30-4377-11f1-90bd-4cf95d479851
2c8eadda-4377-11f1-90bd-4cf95d479851
2c8eae70-4377-11f1-90bd-4cf95d479851
2c8eaefc-4377-11f1-90bd-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)

bdd64a23-b200-8707-87ea-5ce32bd83b97
a9a74b23-b200-8707-87ea-5ce32bd83b97
e82b4c23-b200-8707-87ea-5ce32bd83b97
3f8d4d23-b200-8707-87ea-5ce32bd83b97
6e934e23-b200-8707-87ea-5ce32bd83b97
6e905023-b200-8707-87ea-5ce32bd83b97
0a605123-b200-8707-87ea-5ce32bd83b97
65345223-b200-8707-87ea-5ce32bd83b97
aab45323-b200-8707-87ea-5ce32bd83b97
246e5423-b200-8707-87ea-5ce32bd83b97
e54f5523-b200-8707-87ea-5ce32bd83b97
20825623-b200-8707-87ea-5ce32bd83b97
87cc5723-b200-8707-87ea-5ce32bd83b97
862e5823-b200-8707-87ea-5ce32bd83b97
a9d85923-b200-8707-87ea-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: