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)

019d1460-1f7a-76b1-868c-a30c32b7f2ac
019d1460-1f7a-78b5-813a-9ee558d4a5f9
019d1460-1f7a-79f8-8d51-3cf7b116ca56
019d1460-1f7a-7b1f-8459-e52ca1b46dba
019d1460-1f7a-7c3a-abc3-2cf5067fa396
019d1460-1f7a-7d59-aa7f-6b2337899daa
019d1460-1f7a-7e73-b0a7-e1a47c1781e1
019d1460-1f7a-7f8e-9c2c-c347c72d9c46
019d1460-1f7b-70a8-8b65-6d38f3d17fe7
019d1460-1f7b-71c3-ba7c-f4701b231371
019d1460-1f7b-72de-8248-155ba466f615
019d1460-1f7b-73f8-b983-bfc2135ad077
019d1460-1f7b-74c1-8c9a-3b4a30ab7b26
019d1460-1f7b-75e8-b3c1-0d84f798aaf2
019d1460-1f7b-7707-aa8d-5534880c730c

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)

1f125bdf-e4f0-69be-83b5-4cf95d479851
1f125bdf-e4f0-6b62-83b5-4cf95d479851
1f125bdf-e4f0-6c52-83b5-4cf95d479851
1f125bdf-e4f0-6d24-83b5-4cf95d479851
1f125bdf-e4f0-6dec-83b5-4cf95d479851
1f125bdf-e4f0-6eb4-83b5-4cf95d479851
1f125bdf-e4f0-6f7c-83b5-4cf95d479851
1f125bdf-e4f1-6044-83b5-4cf95d479851
1f125bdf-e4f1-6116-83b5-4cf95d479851
1f125bdf-e4f1-61de-83b5-4cf95d479851
1f125bdf-e4f1-6332-83b5-4cf95d479851
1f125bdf-e4f1-640e-83b5-4cf95d479851
1f125bdf-e4f1-64d6-83b5-4cf95d479851
1f125bdf-e4f1-65a8-83b5-4cf95d479851
1f125bdf-e4f1-6670-83b5-4cf95d479851

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)

b80e5317-6bd0-4cfd-9706-a881befa60dc
2de2194b-7136-4d15-9309-f2392fac7c40
ca93008f-8d74-4e9e-ade3-2a81aee2ce3c
1809743c-8147-4afc-acbe-bb47bfb7ca1e
23a2ca4c-174f-4baf-ad90-0c5fba60eba8
52c50ea9-9e07-4021-8b1f-0f676a50c97f
bd6ae34b-66d9-4bc7-8050-e55a08caf05b
28c90dd1-c0d7-4296-88cc-c76dfc100ff7
d746e792-25df-4da8-98ba-cacb36a756e8
2b26834a-d5a0-4e6e-897f-d4da4ad13054
734e554f-eb28-4c65-bf23-d0bb4caa79a6
b91fbcee-babf-4165-9c59-664dcf26535f
84e1188c-605a-4158-a1d1-903a04ffef0f
04c4b03d-e1b0-463f-99f8-384aefaca08e
a3bbd73c-807e-4fb2-b49c-5cb883d91ab6

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)

fe4f1b98-25bd-11f1-83b5-4cf95d479851
fe4f1bfc-25bd-11f1-83b5-4cf95d479851
fe4f1c56-25bd-11f1-83b5-4cf95d479851
fe4f1cba-25bd-11f1-83b5-4cf95d479851
fe4f1d14-25bd-11f1-83b5-4cf95d479851
fe4f1d6e-25bd-11f1-83b5-4cf95d479851
fe4f1dd2-25bd-11f1-83b5-4cf95d479851
fe4f1e2c-25bd-11f1-83b5-4cf95d479851
fe4f1e90-25bd-11f1-83b5-4cf95d479851
fe4f1efe-25bd-11f1-83b5-4cf95d479851
fe4f1f62-25bd-11f1-83b5-4cf95d479851
fe4f1fbc-25bd-11f1-83b5-4cf95d479851
fe4f2020-25bd-11f1-83b5-4cf95d479851
fe4f208e-25bd-11f1-83b5-4cf95d479851
fe4f20e8-25bd-11f1-83b5-4cf95d479851

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)

79ce1539-ad01-8105-87ea-5ce32bd83b97
8cb51639-ad01-8105-87ea-5ce32bd83b97
eb431739-ad01-8105-87ea-5ce32bd83b97
4c051939-ad01-8105-87ea-5ce32bd83b97
25961a39-ad01-8105-87ea-5ce32bd83b97
1ed01b39-ad01-8105-87ea-5ce32bd83b97
214e1c39-ad01-8105-87ea-5ce32bd83b97
1dc11d39-ad01-8105-87ea-5ce32bd83b97
1d321e39-ad01-8105-87ea-5ce32bd83b97
dfbb1f39-ad01-8105-87ea-5ce32bd83b97
24bb2039-ad01-8105-87ea-5ce32bd83b97
00882139-ad01-8105-87ea-5ce32bd83b97
d8692239-ad01-8105-87ea-5ce32bd83b97
f0972339-ad01-8105-87ea-5ce32bd83b97
8c9b2439-ad01-8105-87ea-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

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: