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)

019ac2d1-14da-7523-bce6-f05f87ab9a63
019ac2d1-14da-76bd-b143-fdc52913b1f2
019ac2d1-14da-7800-916b-c260699950c8
019ac2d1-14da-78b9-a0bb-f62336c861ed
019ac2d1-14da-79d8-9fa5-7983c5e6589d
019ac2d1-14da-7af2-a092-572bf47b2d09
019ac2d1-14da-7c11-a89e-900e8b798845
019ac2d1-14da-7d2c-9584-80867c40c70b
019ac2d1-14da-7e4a-973b-231fa48739e0
019ac2d1-14da-7f61-8fd6-2a4fbad5a936
019ac2d1-14db-707b-8728-c96ae9437f09
019ac2d1-14db-719a-9a9f-ff6796737cc6
019ac2d1-14db-72b5-b561-81f7a9fab2df
019ac2d1-14db-73cf-87d9-f205ca9c14be
019ac2d1-14db-74ea-8fdb-ff2f77084712

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)

1f0cb2c1-abff-6a8c-aad9-4cf95d479851
1f0cb2c1-abff-6c30-aad9-4cf95d479851
1f0cb2c1-abff-6d16-aad9-4cf95d479851
1f0cb2c1-abff-6dde-aad9-4cf95d479851
1f0cb2c1-abff-6e9c-aad9-4cf95d479851
1f0cb2c1-abff-6f5a-aad9-4cf95d479851
1f0cb2c1-ac00-6018-aad9-4cf95d479851
1f0cb2c1-ac00-60d6-aad9-4cf95d479851
1f0cb2c1-ac00-618a-aad9-4cf95d479851
1f0cb2c1-ac00-6248-aad9-4cf95d479851
1f0cb2c1-ac00-637e-aad9-4cf95d479851
1f0cb2c1-ac00-643c-aad9-4cf95d479851
1f0cb2c1-ac00-64f0-aad9-4cf95d479851
1f0cb2c1-ac00-65ae-aad9-4cf95d479851
1f0cb2c1-ac00-6662-aad9-4cf95d479851

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)

bea78d22-d6d6-4040-bce3-7c28538fa15b
08af0b78-5b26-4466-941a-1400457c3ee4
59b447bc-5e3c-489b-881a-df62e56cafca
c6140aed-315f-4621-91f1-1d58df0f65ba
1c87b1c4-dce2-435e-a143-fffe3b31751f
84979838-f869-4f66-b34c-94f566ba09e5
bdf9d845-dff0-4b55-9684-23b8f1fbe9f5
96ceb016-f445-4ab5-9ed0-153503f7271d
a20e4aa6-9aee-4277-9d43-034c183e8bb2
e8ea35b5-3dcd-49c4-8468-766b8f81ab52
422fbb08-df57-40c8-81f8-a98cdedc0da6
a5cc005f-309b-43f5-8aaf-d2d503ff1547
e01d4369-c97e-4b56-8567-b9cd8c5e18f1
65728fb2-890d-49b6-ae91-bdf21a556e28
4f9d41e4-31b8-404d-8d22-b4293bce6b17

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)

1ac00b8a-cb2c-11f0-aad9-4cf95d479851
1ac00be4-cb2c-11f0-aad9-4cf95d479851
1ac00c48-cb2c-11f0-aad9-4cf95d479851
1ac00c98-cb2c-11f0-aad9-4cf95d479851
1ac00cfc-cb2c-11f0-aad9-4cf95d479851
1ac00d56-cb2c-11f0-aad9-4cf95d479851
1ac00db0-cb2c-11f0-aad9-4cf95d479851
1ac00e0a-cb2c-11f0-aad9-4cf95d479851
1ac00e6e-cb2c-11f0-aad9-4cf95d479851
1ac00ebe-cb2c-11f0-aad9-4cf95d479851
1ac00f22-cb2c-11f0-aad9-4cf95d479851
1ac00f86-cb2c-11f0-aad9-4cf95d479851
1ac00fe0-cb2c-11f0-aad9-4cf95d479851
1ac01044-cb2c-11f0-aad9-4cf95d479851
1ac010a8-cb2c-11f0-aad9-4cf95d479851

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)

6717a035-3a00-8b14-87e9-5ce32bd83b97
c1c7a135-3a00-8b14-87e9-5ce32bd83b97
c2d9a235-3a00-8b14-87e9-5ce32bd83b97
db29a335-3a00-8b14-87e9-5ce32bd83b97
ea62a435-3a00-8b14-87e9-5ce32bd83b97
b90ea535-3a00-8b14-87e9-5ce32bd83b97
25f8a635-3a00-8b14-87e9-5ce32bd83b97
56c9a735-3a00-8b14-87e9-5ce32bd83b97
ace0a835-3a00-8b14-87e9-5ce32bd83b97
9653a935-3a00-8b14-87e9-5ce32bd83b97
ce7dab35-3a00-8b14-87e9-5ce32bd83b97
2a3aac35-3a00-8b14-87e9-5ce32bd83b97
d50cad35-3a00-8b14-87e9-5ce32bd83b97
8f38ae35-3a00-8b14-87e9-5ce32bd83b97
430faf35-3a00-8b14-87e9-5ce32bd83b97

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: