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)

019a93b5-4394-768c-9f0c-b01bd14319fc
019a93b5-4394-7819-8d26-48c02c02c5e5
019a93b5-4394-795d-aaf3-9adebb6ee5c2
019a93b5-4394-7a77-a917-3f9e2cb2c07d
019a93b5-4394-7b92-9543-c5cdbc708406
019a93b5-4394-7cad-9e66-53cbeebc9a0f
019a93b5-4394-7dc7-96a5-252e871a5223
019a93b5-4394-7ede-aa47-833cf3152581
019a93b5-4394-7ff4-ae43-dc75991fc6ad
019a93b5-4395-710b-831c-4d585b4e6740
019a93b5-4395-7221-b005-858b389bdf88
019a93b5-4395-733c-bbab-79de4b28606c
019a93b5-4395-7457-950b-1e59222b62e8
019a93b5-4395-758e-ac3c-d110b8ea8a00
019a93b5-4395-76ad-87c1-baaaaae16e6a

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)

1f0c3fbe-c214-6064-b048-4cf95d479851
1f0c3fbe-c214-61fe-b048-4cf95d479851
1f0c3fbe-c214-62f8-b048-4cf95d479851
1f0c3fbe-c214-63ca-b048-4cf95d479851
1f0c3fbe-c214-6492-b048-4cf95d479851
1f0c3fbe-c214-6564-b048-4cf95d479851
1f0c3fbe-c214-662c-b048-4cf95d479851
1f0c3fbe-c214-66f4-b048-4cf95d479851
1f0c3fbe-c214-67b2-b048-4cf95d479851
1f0c3fbe-c214-6870-b048-4cf95d479851
1f0c3fbe-c214-69ba-b048-4cf95d479851
1f0c3fbe-c214-6a8c-b048-4cf95d479851
1f0c3fbe-c214-6b40-b048-4cf95d479851
1f0c3fbe-c214-6bfe-b048-4cf95d479851
1f0c3fbe-c214-6cc6-b048-4cf95d479851

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)

dd00bac6-a3f0-4850-92f7-a2753413b638
1c7c4887-cb95-4337-a416-258a1049166c
f80d4467-82d9-4a03-834e-2d8927d822c6
6795e3d6-c423-4317-bbf4-f196d0def856
cbe9eca4-e088-4f33-97ad-ac13e1c9f715
3e488d47-fc02-4850-906d-3abf4b8cb08e
8dadad8f-ed98-464b-9661-26abc97dd275
0a1b8db6-efee-4a21-b9cf-d0b458f4b380
a12d8acd-bcef-4289-bea7-43a6f38bf9ac
ddc9e4e7-06f4-4b18-8e00-fdf8510289b0
7041ff02-4c1e-4de4-bc32-6d48df6685c0
ff56b8b3-85c2-4a91-8fbf-d6c56fd8218f
19be3d14-d4f2-4403-a242-40f8ab206b19
d6b5bd95-928f-4ee7-b584-edebefd22ef0
80493a5b-54a7-4d2a-bde8-129db36fae47

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)

ec2151ee-c3fb-11f0-b048-4cf95d479851
ec215252-c3fb-11f0-b048-4cf95d479851
ec2152b6-c3fb-11f0-b048-4cf95d479851
ec21531a-c3fb-11f0-b048-4cf95d479851
ec21537e-c3fb-11f0-b048-4cf95d479851
ec2153e2-c3fb-11f0-b048-4cf95d479851
ec215446-c3fb-11f0-b048-4cf95d479851
ec2154b4-c3fb-11f0-b048-4cf95d479851
ec215518-c3fb-11f0-b048-4cf95d479851
ec215572-c3fb-11f0-b048-4cf95d479851
ec2155d6-c3fb-11f0-b048-4cf95d479851
ec21563a-c3fb-11f0-b048-4cf95d479851
ec21569e-c3fb-11f0-b048-4cf95d479851
ec215702-c3fb-11f0-b048-4cf95d479851
ec215766-c3fb-11f0-b048-4cf95d479851

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)

60cd6e15-0605-8114-87e9-5ce32bd83b97
4e916f15-0605-8114-87e9-5ce32bd83b97
33f07015-0605-8114-87e9-5ce32bd83b97
9ea17115-0605-8114-87e9-5ce32bd83b97
8c567215-0605-8114-87e9-5ce32bd83b97
76e67315-0605-8114-87e9-5ce32bd83b97
ed7a7415-0605-8114-87e9-5ce32bd83b97
3a997515-0605-8114-87e9-5ce32bd83b97
627a7615-0605-8114-87e9-5ce32bd83b97
803b7715-0605-8114-87e9-5ce32bd83b97
e3287815-0605-8114-87e9-5ce32bd83b97
90187915-0605-8114-87e9-5ce32bd83b97
b4f27a15-0605-8114-87e9-5ce32bd83b97
1fb77b15-0605-8114-87e9-5ce32bd83b97
2b3e7c15-0605-8114-87e9-5ce32bd83b97

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: