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)

019e0ed8-330d-7769-8353-dd3b33f3f533
019e0ed8-330d-7903-85fc-30fe59977418
019e0ed8-330d-7a42-ada2-4b8dfd9916aa
019e0ed8-330d-7b65-aa30-12ab0edd9eec
019e0ed8-330d-7c84-8ad8-94051cbc3f39
019e0ed8-330d-7d9e-a4c3-8abaf4ca3b3a
019e0ed8-330d-7ebd-b523-e8323a91c2c6
019e0ed8-330d-7fd3-9ab1-535140ed1ef2
019e0ed8-330e-70a4-a58c-005e3d7c68a7
019e0ed8-330e-71e0-a7cc-9dd8e4dd096f
019e0ed8-330e-7317-8307-33c99c256d54
019e0ed8-330e-744e-aff4-2b7bec8cc611
019e0ed8-330e-7582-9baf-4ff54e4bd13e
019e0ed8-330e-76b9-a3a6-f509ba814645
019e0ed8-330e-77f4-b523-9880555687ca

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)

1f14bf5f-0cba-6bfe-8477-4cf95d479851
1f14bf5f-0cba-6d98-8477-4cf95d479851
1f14bf5f-0cba-6e7e-8477-4cf95d479851
1f14bf5f-0cba-6f50-8477-4cf95d479851
1f14bf5f-0cbb-6022-8477-4cf95d479851
1f14bf5f-0cbb-60e0-8477-4cf95d479851
1f14bf5f-0cbb-61a8-8477-4cf95d479851
1f14bf5f-0cbb-6270-8477-4cf95d479851
1f14bf5f-0cbb-632e-8477-4cf95d479851
1f14bf5f-0cbb-63ec-8477-4cf95d479851
1f14bf5f-0cbb-652c-8477-4cf95d479851
1f14bf5f-0cbb-65f4-8477-4cf95d479851
1f14bf5f-0cbb-66bc-8477-4cf95d479851
1f14bf5f-0cbb-677a-8477-4cf95d479851
1f14bf5f-0cbb-6838-8477-4cf95d479851

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)

20d89b16-7ea7-42d1-a593-7c7de15793f3
012edea4-4875-455b-8446-3b27cd1e058f
1b563fc1-86f3-4e9e-9f0c-05ad1e0f06ca
1c81b314-61c4-4019-b994-bed081392fab
d426f81f-7b72-4b83-ad19-8c2f50d8608f
b6777843-cdbb-4757-b812-6322641703bf
5acffa7b-7836-43d1-b995-0f46f3dca9d1
88dec625-ba6e-47be-a414-54e012730778
e2fd86b4-4046-442e-a895-c298576f47e0
d3950821-34d0-4bdc-92d9-7f6772b4674f
2b0887c5-9873-4db1-a2a5-ce51d4b88bc0
258fba64-e1cf-418f-8729-682fc9f4b4dc
550fca0b-eeca-4ef0-a615-b4312d1b6b63
3501cfcb-3ea8-4d54-8bd5-81b848b79bde
c33e6868-a5f5-43ed-a0e9-e5fe2d1e437e

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)

f0cbbd60-4bf5-11f1-8477-4cf95d479851
f0cbbdc4-4bf5-11f1-8477-4cf95d479851
f0cbbe32-4bf5-11f1-8477-4cf95d479851
f0cbbea0-4bf5-11f1-8477-4cf95d479851
f0cbbf04-4bf5-11f1-8477-4cf95d479851
f0cbbf68-4bf5-11f1-8477-4cf95d479851
f0cbbfcc-4bf5-11f1-8477-4cf95d479851
f0cbc030-4bf5-11f1-8477-4cf95d479851
f0cbc094-4bf5-11f1-8477-4cf95d479851
f0cbc0f8-4bf5-11f1-8477-4cf95d479851
f0cbc15c-4bf5-11f1-8477-4cf95d479851
f0cbc1b6-4bf5-11f1-8477-4cf95d479851
f0cbc224-4bf5-11f1-8477-4cf95d479851
f0cbc27e-4bf5-11f1-8477-4cf95d479851
f0cbc2e2-4bf5-11f1-8477-4cf95d479851

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)
-  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)

49786a0a-4205-8108-87ea-5ce32bd83b97
3b816b0a-4205-8108-87ea-5ce32bd83b97
90286c0a-4205-8108-87ea-5ce32bd83b97
84236d0a-4205-8108-87ea-5ce32bd83b97
c9a06e0a-4205-8108-87ea-5ce32bd83b97
dcfe6f0a-4205-8108-87ea-5ce32bd83b97
dded700a-4205-8108-87ea-5ce32bd83b97
c2c9710a-4205-8108-87ea-5ce32bd83b97
89bd720a-4205-8108-87ea-5ce32bd83b97
c335730a-4205-8108-87ea-5ce32bd83b97
0852740a-4205-8108-87ea-5ce32bd83b97
72a0750a-4205-8108-87ea-5ce32bd83b97
7199760a-4205-8108-87ea-5ce32bd83b97
4c01770a-4205-8108-87ea-5ce32bd83b97
6956780a-4205-8108-87ea-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: