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)

01a15eb6-8743-74bd-af14-4e53183d1293
01a15eb6-8743-769c-9f39-8232bf0f77e3
01a15eb6-8743-77e4-bec2-8d6bbb4884c7
01a15eb6-8743-7903-afb3-804efdd5f2b6
01a15eb6-8743-7a1d-a1b0-3791e5ffcceb
01a15eb6-8743-7b3c-9ea9-fa9dd999f5aa
01a15eb6-8743-7c57-a4e5-94a23e2a12d7
01a15eb6-8743-7d6d-b048-569a9403d19e
01a15eb6-8743-7e84-8e14-af99eb751f18
01a15eb6-8743-7f9a-a130-c10c78301c51
01a15eb6-8744-70b1-b21d-48e2314a2c7c
01a15eb6-8744-71cb-b9de-80334d95d47b
01a15eb6-8744-72e6-bccf-bd320bc00574
01a15eb6-8744-740d-9c2d-f1babbb55ec1
01a15eb6-8744-7527-a22c-0fb28b2bb95e

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)

1f1cd55c-d852-64d6-b89a-4cf95d479851
1f1cd55c-d852-66f2-b89a-4cf95d479851
1f1cd55c-d852-67d8-b89a-4cf95d479851
1f1cd55c-d852-68b4-b89a-4cf95d479851
1f1cd55c-d852-6990-b89a-4cf95d479851
1f1cd55c-d852-6a4e-b89a-4cf95d479851
1f1cd55c-d852-6b16-b89a-4cf95d479851
1f1cd55c-d852-6bde-b89a-4cf95d479851
1f1cd55c-d852-6c9c-b89a-4cf95d479851
1f1cd55c-d852-6d5a-b89a-4cf95d479851
1f1cd55c-d852-6f1c-b89a-4cf95d479851
1f1cd55c-d853-6070-b89a-4cf95d479851
1f1cd55c-d853-61c4-b89a-4cf95d479851
1f1cd55c-d853-62aa-b89a-4cf95d479851
1f1cd55c-d853-6368-b89a-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)

cd85344e-cd55-11f1-b89a-4cf95d479851
cd8534b2-cd55-11f1-b89a-4cf95d479851
cd853516-cd55-11f1-b89a-4cf95d479851
cd85357a-cd55-11f1-b89a-4cf95d479851
cd8535de-cd55-11f1-b89a-4cf95d479851
cd85364c-cd55-11f1-b89a-4cf95d479851
cd8536ba-cd55-11f1-b89a-4cf95d479851
cd85371e-cd55-11f1-b89a-4cf95d479851
cd85378c-cd55-11f1-b89a-4cf95d479851
cd8537f0-cd55-11f1-b89a-4cf95d479851
cd853854-cd55-11f1-b89a-4cf95d479851
cd8538b8-cd55-11f1-b89a-4cf95d479851
cd853912-cd55-11f1-b89a-4cf95d479851
cd853980-cd55-11f1-b89a-4cf95d479851
cd8539e4-cd55-11f1-b89a-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)

61ebea16-3b03-8612-87ea-5ce32bd83b97
4d32eb16-3b03-8612-87ea-5ce32bd83b97
f758ec16-3b03-8612-87ea-5ce32bd83b97
fed1ed16-3b03-8612-87ea-5ce32bd83b97
4a2dee16-3b03-8612-87ea-5ce32bd83b97
f757ef16-3b03-8612-87ea-5ce32bd83b97
ea8af016-3b03-8612-87ea-5ce32bd83b97
2bd8f116-3b03-8612-87ea-5ce32bd83b97
ea25f216-3b03-8612-87ea-5ce32bd83b97
d88cf416-3b03-8612-87ea-5ce32bd83b97
fd53f516-3b03-8612-87ea-5ce32bd83b97
3c81f616-3b03-8612-87ea-5ce32bd83b97
6828f716-3b03-8612-87ea-5ce32bd83b97
e251f816-3b03-8612-87ea-5ce32bd83b97
fdd9f916-3b03-8612-87ea-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)

44487e63-5e7b-4e69-9c71-e924bd4b76c5
cf3b228f-ca08-4ca5-a2b7-68fb2fb6d48e
34ef253f-e9cb-44f5-a495-cfe73fb76b46
a4b01323-4f7c-4451-9b8e-3ff1216b37c4
da961403-5bca-4d94-be92-fa0f133c5c67
82b24aa5-499f-4906-a8ac-0b4d89f4c863
9329d3cc-f8b1-4f93-b531-67c98be8c1e6
da100103-4d80-41f0-abd8-046dcd4b6a07
91ebf543-510b-4ff1-9fd4-5f410ca2a6d0
619fe467-1262-4c95-910d-f8c2689c558a
30c9d0be-2f88-4391-bb6f-22f219acfbd9
6ffcfbb3-5d18-4d1e-83a5-c0e8f9be8ee4
f10e7988-a6a9-4d86-b896-0a10f1e5db06
5bd7ba74-a271-4730-9a42-c1b4a9b0aefb
5dc6d341-3a96-487a-bd67-fedaa8bbcda1

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: