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)

01a1af88-1157-743a-8cfb-bee99104b917
01a1af88-1157-7642-8d8b-e27df5798666
01a1af88-1157-7786-9ce0-380080167ff5
01a1af88-1157-78a0-810e-5ef106f91df6
01a1af88-1157-79b7-95f6-8035c16bc5b6
01a1af88-1157-7ada-9af6-3108f652163e
01a1af88-1157-7bf4-a7a4-f2a69f869309
01a1af88-1157-7d0b-b6bd-136323f9b703
01a1af88-1157-7e94-84e2-1b1b7459fd98
01a1af88-1157-7fb7-ad8d-1dd5710a7fe0
01a1af88-1158-70cd-a285-6f176004f20d
01a1af88-1158-71e4-b740-20b219164d5a
01a1af88-1158-730b-9435-452b6b07899c
01a1af88-1158-7425-b4d6-21e820563313
01a1af88-1158-753c-8f15-f587aa6fbef4

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)

1f1d9aac-6a6c-6e9c-8477-4cf95d479851
1f1d9aac-6a6d-604a-8477-4cf95d479851
1f1d9aac-6a6d-613a-8477-4cf95d479851
1f1d9aac-6a6d-6216-8477-4cf95d479851
1f1d9aac-6a6d-62e8-8477-4cf95d479851
1f1d9aac-6a6d-63b0-8477-4cf95d479851
1f1d9aac-6a6d-6478-8477-4cf95d479851
1f1d9aac-6a6d-6540-8477-4cf95d479851
1f1d9aac-6a6d-65fe-8477-4cf95d479851
1f1d9aac-6a6d-66c6-8477-4cf95d479851
1f1d9aac-6a6d-6806-8477-4cf95d479851
1f1d9aac-6a6d-68d8-8477-4cf95d479851
1f1d9aac-6a6d-69aa-8477-4cf95d479851
1f1d9aac-6a6d-6a68-8477-4cf95d479851
1f1d9aac-6a6d-6b26-8477-4cf95d479851

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)

c6a6dc0c-d9aa-11f1-8477-4cf95d479851
c6a6dc70-d9aa-11f1-8477-4cf95d479851
c6a6dcd4-d9aa-11f1-8477-4cf95d479851
c6a6dd42-d9aa-11f1-8477-4cf95d479851
c6a6dda6-d9aa-11f1-8477-4cf95d479851
c6a6de14-d9aa-11f1-8477-4cf95d479851
c6a6de6e-d9aa-11f1-8477-4cf95d479851
c6a6ded2-d9aa-11f1-8477-4cf95d479851
c6a6df36-d9aa-11f1-8477-4cf95d479851
c6a6df9a-d9aa-11f1-8477-4cf95d479851
c6a6dffe-d9aa-11f1-8477-4cf95d479851
c6a6e058-d9aa-11f1-8477-4cf95d479851
c6a6e0bc-d9aa-11f1-8477-4cf95d479851
c6a6e120-d9aa-11f1-8477-4cf95d479851
c6a6e17a-d9aa-11f1-8477-4cf95d479851

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)

083c9134-8101-8613-87ea-5ce32bd83b97
87d69234-8101-8613-87ea-5ce32bd83b97
c3579334-8101-8613-87ea-5ce32bd83b97
9bd99434-8101-8613-87ea-5ce32bd83b97
aa6c9534-8101-8613-87ea-5ce32bd83b97
e8bf9634-8101-8613-87ea-5ce32bd83b97
f3c99734-8101-8613-87ea-5ce32bd83b97
56c49834-8101-8613-87ea-5ce32bd83b97
54ed9934-8101-8613-87ea-5ce32bd83b97
ba819a34-8101-8613-87ea-5ce32bd83b97
c83a9b34-8101-8613-87ea-5ce32bd83b97
44a59c34-8101-8613-87ea-5ce32bd83b97
68da9d34-8101-8613-87ea-5ce32bd83b97
c78e9f34-8101-8613-87ea-5ce32bd83b97
61eea034-8101-8613-87ea-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)

469139bf-9daf-443e-a905-9227d4d4a392
ab150c2a-8089-4446-afd4-ed577b803634
ca51ecde-61ea-40ef-b464-ba5c5bd6e0f0
8c9e4953-1fae-48c5-801b-a22544ba5c5b
9291f06c-47ec-4604-b808-4e65e8c0fd43
db464ba1-fa24-4904-a778-f0d4b06a50cc
4d9e2496-c7ca-4774-bb25-7e8ceb241975
40ab11dc-d134-4f9d-8759-850a6f5ccb80
493ac3a1-e57c-4065-adb6-0180e8b70312
bf621c08-abed-44ce-9575-29eb5aa95839
e8cb06c7-c562-45ed-b46d-7ac79ce43ded
3849ddd6-0b8f-48cd-af61-435bc3b20dc0
cd91c964-c165-4ca4-bc04-619d4a55e054
281a9d83-2bb4-4b51-9f5a-a8c0fc59e103
101b74fc-46e4-4cbb-8494-39b159cdc640

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: