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)

019cba8a-afd4-762e-8a07-541daad082e0
019cba8a-afd4-77c7-b44e-d572fed426c4
019cba8a-afd4-790f-ad58-a3302ea81964
019cba8a-afd4-7a32-839d-2478edb3a0bd
019cba8a-afd4-7b50-9187-b3c701331f61
019cba8a-afd4-7c6b-ae3c-262a08747f9c
019cba8a-afd4-7d86-81fb-d75564a59e97
019cba8a-afd4-7e9c-8c89-ef7144af2c25
019cba8a-afd4-7fb3-a515-368cf5f85b00
019cba8a-afd5-70c9-b42b-4f8120f5699f
019cba8a-afd5-71e4-b0c4-09ab10097301
019cba8a-afd5-72fe-a215-33011fe74442
019cba8a-afd5-7415-811d-81f56eeac34a
019cba8a-afd5-7530-adb9-bfa0af6f4409
019cba8a-afd5-7646-8e7f-40dd9a827e0e

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)

1f11808d-cf5c-636a-8c82-4cf95d479851
1f11808d-cf5c-650e-8c82-4cf95d479851
1f11808d-cf5c-65fe-8c82-4cf95d479851
1f11808d-cf5c-66c6-8c82-4cf95d479851
1f11808d-cf5c-678e-8c82-4cf95d479851
1f11808d-cf5c-684c-8c82-4cf95d479851
1f11808d-cf5c-6914-8c82-4cf95d479851
1f11808d-cf5c-69d2-8c82-4cf95d479851
1f11808d-cf5c-6a9a-8c82-4cf95d479851
1f11808d-cf5c-6b58-8c82-4cf95d479851
1f11808d-cf5c-6ca2-8c82-4cf95d479851
1f11808d-cf5c-6d6a-8c82-4cf95d479851
1f11808d-cf5c-6e32-8c82-4cf95d479851
1f11808d-cf5c-6f04-8c82-4cf95d479851
1f11808d-cf5c-6fcc-8c82-4cf95d479851

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)

ed2dbf6e-e1ff-4dde-a91a-6f8bda777fee
b75d72a1-e4af-4176-9ac2-62b6517601c4
a2bea80d-22d1-4195-b73f-d4cc3ac93733
5e877b75-d9b1-45e8-84bc-3ef106995927
cc311335-5599-4d5f-b577-6e8529a48409
12c1f252-4e5f-4be2-82c5-052a13889d90
1006878d-e1dc-4858-a6c5-bc45e39267f0
952f6b4d-eb81-495c-a982-fe4f49bcb8aa
3ff80fbc-b785-4a77-88d5-1ea315f1ed0b
9f5434b7-b380-4ed9-ae9c-9ce820a4626d
637ba3a1-8720-4f54-a4e8-3f4c9788b7dd
b6737b5a-6376-442b-87d4-02034a0ac334
0a9a50cd-d52a-4a7d-9a35-846466364d60
445c861f-68d2-4503-8661-c323e1bdfadc
b62a0edf-068d-421c-82f0-030c9c3cd211

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)

dcf5d4fe-1808-11f1-8c82-4cf95d479851
dcf5d562-1808-11f1-8c82-4cf95d479851
dcf5d5c6-1808-11f1-8c82-4cf95d479851
dcf5d620-1808-11f1-8c82-4cf95d479851
dcf5d684-1808-11f1-8c82-4cf95d479851
dcf5d6e8-1808-11f1-8c82-4cf95d479851
dcf5d74c-1808-11f1-8c82-4cf95d479851
dcf5d7b0-1808-11f1-8c82-4cf95d479851
dcf5d814-1808-11f1-8c82-4cf95d479851
dcf5d882-1808-11f1-8c82-4cf95d479851
dcf5d8f0-1808-11f1-8c82-4cf95d479851
dcf5d94a-1808-11f1-8c82-4cf95d479851
dcf5d9ae-1808-11f1-8c82-4cf95d479851
dcf5da08-1808-11f1-8c82-4cf95d479851
dcf5da6c-1808-11f1-8c82-4cf95d479851

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)

0c351c25-ce04-8f03-87ea-5ce32bd83b97
ee451d25-ce04-8f03-87ea-5ce32bd83b97
995f1e25-ce04-8f03-87ea-5ce32bd83b97
32891f25-ce04-8f03-87ea-5ce32bd83b97
18ba2025-ce04-8f03-87ea-5ce32bd83b97
803e2125-ce04-8f03-87ea-5ce32bd83b97
2b2d2225-ce04-8f03-87ea-5ce32bd83b97
7ef62325-ce04-8f03-87ea-5ce32bd83b97
ea3d2425-ce04-8f03-87ea-5ce32bd83b97
f4002525-ce04-8f03-87ea-5ce32bd83b97
86b22625-ce04-8f03-87ea-5ce32bd83b97
08522725-ce04-8f03-87ea-5ce32bd83b97
a92f2925-ce04-8f03-87ea-5ce32bd83b97
2a422a25-ce04-8f03-87ea-5ce32bd83b97
2edd2b25-ce04-8f03-87ea-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: