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)

019ce5d8-41c9-723a-a77d-d5543fea10a2
019ce5d8-41c9-73f4-bf6c-40cdbc3dd895
019ce5d8-41c9-7538-bf6d-6c6c80ca4edf
019ce5d8-41c9-765b-bc86-29572592b0b1
019ce5d8-41c9-7775-85dd-68e19713ad59
019ce5d8-41c9-7890-83f7-c8c2e457d56d
019ce5d8-41c9-79aa-9138-fa59c304f6ee
019ce5d8-41c9-7ac5-950e-5268d2dfc16a
019ce5d8-41c9-7be4-a9ef-9a9d00f0f58d
019ce5d8-41c9-7cfe-b7ee-02c8de0763c7
019ce5d8-41c9-7e15-b534-e4050733956e
019ce5d8-41c9-7f30-8c44-468fdadaaeb4
019ce5d8-41ca-704a-9f1d-047eb984b27e
019ce5d8-41ca-7165-9de8-99e46362193c
019ce5d8-41ca-727b-8abe-7493140de731

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)

1f11ea46-30b2-6e26-aadf-4cf95d479851
1f11ea46-30b2-6fd4-aadf-4cf95d479851
1f11ea46-30b3-60ba-aadf-4cf95d479851
1f11ea46-30b3-6182-aadf-4cf95d479851
1f11ea46-30b3-624a-aadf-4cf95d479851
1f11ea46-30b3-6308-aadf-4cf95d479851
1f11ea46-30b3-63d0-aadf-4cf95d479851
1f11ea46-30b3-648e-aadf-4cf95d479851
1f11ea46-30b3-654c-aadf-4cf95d479851
1f11ea46-30b3-660a-aadf-4cf95d479851
1f11ea46-30b3-6754-aadf-4cf95d479851
1f11ea46-30b3-681c-aadf-4cf95d479851
1f11ea46-30b3-68da-aadf-4cf95d479851
1f11ea46-30b3-6998-aadf-4cf95d479851
1f11ea46-30b3-6a56-aadf-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)

daafe7ce-7f00-41f8-b9a9-8f354d9287a0
a562a177-77b7-435a-a8dc-4664f34954c8
18c5d304-0b6d-4403-b8ee-23b1837e6dce
35dff38c-48d7-4975-b26d-d3fc9f2dee42
477792a0-93d4-44e3-a4a8-881c3da67d44
c483fac0-e45d-4dca-91e4-637b3e1e94a9
c825ff73-c875-4266-a667-4aa8b0ca7da3
556df527-e8ee-4d81-9902-2534ab52fc09
8b8307e6-8dc8-4243-9b79-5885a5e6b1bd
5bf67dd8-d96f-415b-b197-7727f3a6860c
0ffcad01-100a-4c17-b396-ed53e6e07bd4
bfb06655-7964-4470-9372-b01584e6d8be
3c5ee524-dc3c-4443-a6aa-c126a8cfd150
783b8edd-e715-4a8f-8ebf-aa8801e33990
dc363e37-0a58-4435-adc2-42e31546abf6

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)

630b3f7e-1ea4-11f1-aadf-4cf95d479851
630b3fe2-1ea4-11f1-aadf-4cf95d479851
630b4050-1ea4-11f1-aadf-4cf95d479851
630b40aa-1ea4-11f1-aadf-4cf95d479851
630b4118-1ea4-11f1-aadf-4cf95d479851
630b417c-1ea4-11f1-aadf-4cf95d479851
630b41d6-1ea4-11f1-aadf-4cf95d479851
630b4230-1ea4-11f1-aadf-4cf95d479851
630b4294-1ea4-11f1-aadf-4cf95d479851
630b42f8-1ea4-11f1-aadf-4cf95d479851
630b4352-1ea4-11f1-aadf-4cf95d479851
630b43ac-1ea4-11f1-aadf-4cf95d479851
630b4410-1ea4-11f1-aadf-4cf95d479851
630b4500-1ea4-11f1-aadf-4cf95d479851
630b4564-1ea4-11f1-aadf-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)

45760901-7b01-8804-87ea-5ce32bd83b97
a7860a01-7b01-8804-87ea-5ce32bd83b97
79d40b01-7b01-8804-87ea-5ce32bd83b97
a6680c01-7b01-8804-87ea-5ce32bd83b97
5c0a0d01-7b01-8804-87ea-5ce32bd83b97
dbd30e01-7b01-8804-87ea-5ce32bd83b97
a89c0f01-7b01-8804-87ea-5ce32bd83b97
f0991001-7b01-8804-87ea-5ce32bd83b97
70fa1101-7b01-8804-87ea-5ce32bd83b97
b5b11201-7b01-8804-87ea-5ce32bd83b97
b1841301-7b01-8804-87ea-5ce32bd83b97
2c411401-7b01-8804-87ea-5ce32bd83b97
bb5b1501-7b01-8804-87ea-5ce32bd83b97
9c281601-7b01-8804-87ea-5ce32bd83b97
e9411701-7b01-8804-87ea-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: