UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019fe42b-1af3-7f79-ac02-fb1ca3ef9229
019fe42b-1af4-713c-b7c9-a3d0fdca10ee
019fe42b-1af4-7290-b304-7df4a54b73f1
019fe42b-1af4-73b7-b929-d22a93b0e742
019fe42b-1af4-74da-9ad3-4803447e79de
019fe42b-1af4-75f8-bd1b-a0f006f1596f
019fe42b-1af4-771b-ab12-8bd9c46ee3c0
019fe42b-1af4-783a-8f5f-a8eb9b321280
019fe42b-1af4-7959-803b-bd2a557291a7
019fe42b-1af4-7a77-8d1c-bc5624ab2d9c
019fe42b-1af4-7b9a-b7f9-6463df2af18b
019fe42b-1af4-7cbd-8df9-93e024728fd0
019fe42b-1af4-7ddc-a479-f0b7860023a7
019fe42b-1af4-7efa-a462-681eaeb328a5
019fe42b-1af5-7019-a28c-253d2d7c3b9e

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)

1f19392e-74e4-66e2-9063-4cf95d479851
1f19392e-74e4-68e0-9063-4cf95d479851
1f19392e-74e4-69d0-9063-4cf95d479851
1f19392e-74e4-6ab6-9063-4cf95d479851
1f19392e-74e4-6b88-9063-4cf95d479851
1f19392e-74e4-6c5a-9063-4cf95d479851
1f19392e-74e4-6d22-9063-4cf95d479851
1f19392e-74e4-6df4-9063-4cf95d479851
1f19392e-74e4-6ed0-9063-4cf95d479851
1f19392e-74e4-6fa2-9063-4cf95d479851
1f19392e-74e5-613c-9063-4cf95d479851
1f19392e-74e5-6222-9063-4cf95d479851
1f19392e-74e5-62f4-9063-4cf95d479851
1f19392e-74e5-63c6-9063-4cf95d479851
1f19392e-74e5-648e-9063-4cf95d479851

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)

e74e5574-9392-11f1-9063-4cf95d479851
e74e55d8-9392-11f1-9063-4cf95d479851
e74e563c-9392-11f1-9063-4cf95d479851
e74e56a0-9392-11f1-9063-4cf95d479851
e74e56fa-9392-11f1-9063-4cf95d479851
e74e575e-9392-11f1-9063-4cf95d479851
e74e57b8-9392-11f1-9063-4cf95d479851
e74e5812-9392-11f1-9063-4cf95d479851
e74e5876-9392-11f1-9063-4cf95d479851
e74e58d0-9392-11f1-9063-4cf95d479851
e74e593e-9392-11f1-9063-4cf95d479851
e74e59a2-9392-11f1-9063-4cf95d479851
e74e5a06-9392-11f1-9063-4cf95d479851
e74e5a6a-9392-11f1-9063-4cf95d479851
e74e5ace-9392-11f1-9063-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

01280926-6200-8d0d-87ea-5ce32bd83b97
38d00a26-6200-8d0d-87ea-5ce32bd83b97
64630b26-6200-8d0d-87ea-5ce32bd83b97
77350d26-6200-8d0d-87ea-5ce32bd83b97
e6790e26-6200-8d0d-87ea-5ce32bd83b97
96130f26-6200-8d0d-87ea-5ce32bd83b97
8ba71026-6200-8d0d-87ea-5ce32bd83b97
1ac51126-6200-8d0d-87ea-5ce32bd83b97
df571226-6200-8d0d-87ea-5ce32bd83b97
cd361326-6200-8d0d-87ea-5ce32bd83b97
319d1426-6200-8d0d-87ea-5ce32bd83b97
05131526-6200-8d0d-87ea-5ce32bd83b97
a1be1626-6200-8d0d-87ea-5ce32bd83b97
d4b61726-6200-8d0d-87ea-5ce32bd83b97
bf471826-6200-8d0d-87ea-5ce32bd83b97

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)

76f761e2-04c7-49ad-930b-1e066f967f86
1aa9b76d-9734-4d99-9527-4565f8e3b3e8
cd3418fe-75b8-4f7b-a878-966a5e675bce
73f91cd6-4df8-4749-bd35-95ac65857d14
52c45628-c4d2-4627-a157-b9027274bcf5
79b73aa0-a8a9-4a8f-aa8d-06a3142ebc75
23c3dae0-36d0-4bf2-b6e4-e0bfb64ca032
b5d3c02f-2fc7-4140-a424-3476c196a5f3
dc18d742-b3a2-40a2-8643-996f996c9551
6086f2c1-a008-4a04-9d9a-c655d8ec52a7
f4653387-8b76-4e7a-a3f3-7a3a02912f8e
1d9cf9ab-b319-4579-a21d-e5269d516b8a
a84b5c7f-f135-4a60-906b-3da2355430e4
b3a4d7f1-3ee2-4594-8ccd-e30244fe5af5
62acd0a3-070b-498e-b6b7-3aae1a697afc

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: