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)

01a1799f-0898-798e-a104-dda657d218d3
01a1799f-0898-7b0b-92ef-f717c6bb9561
01a1799f-0898-7c46-89e7-256962c33e2c
01a1799f-0898-7d61-9aeb-db3b289ca8f2
01a1799f-0898-7e77-a160-de6702e9ce96
01a1799f-0898-7f8e-a64c-6ab8ca2b1b44
01a1799f-0899-70a4-9528-8b39330f85f9
01a1799f-0899-71bb-ab4f-0da923f10b12
01a1799f-0899-72d1-aa9f-7fdc2f64d1f3
01a1799f-0899-73f4-ab41-950639489cb0
01a1799f-0899-7527-b17b-3581c360e820
01a1799f-0899-7642-9a46-f91db2f9f045
01a1799f-0899-7759-be44-7cc1ac7b19e6
01a1799f-0899-7877-acaf-1e109d0e7f62
01a1799f-0899-798e-9909-9b82afd3e15e

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)

1f1d170e-7c13-63b6-ba23-4cf95d479851
1f1d170e-7c13-6550-ba23-4cf95d479851
1f1d170e-7c13-6640-ba23-4cf95d479851
1f1d170e-7c13-6712-ba23-4cf95d479851
1f1d170e-7c13-67da-ba23-4cf95d479851
1f1d170e-7c13-68a2-ba23-4cf95d479851
1f1d170e-7c13-696a-ba23-4cf95d479851
1f1d170e-7c13-6a32-ba23-4cf95d479851
1f1d170e-7c13-6af0-ba23-4cf95d479851
1f1d170e-7c13-6bb8-ba23-4cf95d479851
1f1d170e-7c13-6d20-ba23-4cf95d479851
1f1d170e-7c13-6df2-ba23-4cf95d479851
1f1d170e-7c13-6eba-ba23-4cf95d479851
1f1d170e-7c13-6f78-ba23-4cf95d479851
1f1d170e-7c14-6036-ba23-4cf95d479851

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)

e7c14112-d170-11f1-ba23-4cf95d479851
e7c14176-d170-11f1-ba23-4cf95d479851
e7c141d0-d170-11f1-ba23-4cf95d479851
e7c14234-d170-11f1-ba23-4cf95d479851
e7c14298-d170-11f1-ba23-4cf95d479851
e7c142f2-d170-11f1-ba23-4cf95d479851
e7c14356-d170-11f1-ba23-4cf95d479851
e7c143ba-d170-11f1-ba23-4cf95d479851
e7c1441e-d170-11f1-ba23-4cf95d479851
e7c1448c-d170-11f1-ba23-4cf95d479851
e7c144f0-d170-11f1-ba23-4cf95d479851
e7c14554-d170-11f1-ba23-4cf95d479851
e7c145ae-d170-11f1-ba23-4cf95d479851
e7c14612-d170-11f1-ba23-4cf95d479851
e7c14676-d170-11f1-ba23-4cf95d479851

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)

ce38fe1b-7f04-8b12-87ea-5ce32bd83b97
fdd0ff1b-7f04-8b12-87ea-5ce32bd83b97
afbc011c-7f04-8b12-87ea-5ce32bd83b97
0321021c-7f04-8b12-87ea-5ce32bd83b97
e19f031c-7f04-8b12-87ea-5ce32bd83b97
f59d041c-7f04-8b12-87ea-5ce32bd83b97
daae051c-7f04-8b12-87ea-5ce32bd83b97
f10f061c-7f04-8b12-87ea-5ce32bd83b97
bcd6071c-7f04-8b12-87ea-5ce32bd83b97
1a32081c-7f04-8b12-87ea-5ce32bd83b97
990c091c-7f04-8b12-87ea-5ce32bd83b97
47820a1c-7f04-8b12-87ea-5ce32bd83b97
ebd10b1c-7f04-8b12-87ea-5ce32bd83b97
880d0c1c-7f04-8b12-87ea-5ce32bd83b97
4a730d1c-7f04-8b12-87ea-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)

aac0e8d6-393a-460c-a374-cdcfd97ec5d0
d817625c-efeb-4463-a6a0-5b4b810ef6f6
89b63f42-2eef-4c45-aaea-7fc034948d9d
a697ef98-2d38-4210-933b-507eee4b20f4
ecd1e252-90df-4831-b2ff-a9541b30e535
c9eabe41-d7ab-4ac4-bb74-8d75278f1e31
53a01cb8-0f2b-44dc-8d97-172079237f33
6689f29e-5746-4793-aadc-a8318606ddf4
4e16ce8c-9d9e-4e18-9bb0-6bf2bb488d43
f0286580-4390-4d86-96e6-f5bf7a6c7767
df421b08-82c2-43da-ac8d-b9b3d3062981
c511e172-1d8f-418d-b6ad-e99d33cda98f
c914c87b-cf03-40fa-acba-90f938885129
108b7677-0ba6-4d0f-8046-086141acda8d
60dd465d-3d53-4617-aeec-404772b8ca57

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: