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)

019eb63a-6ba2-7c21-ac47-9302720595d8
019eb63a-6ba2-7da2-9125-87d9e9d83d4f
019eb63a-6ba2-7eda-966b-58448f54c49d
019eb63a-6ba2-7ff8-817a-0a50a0006d71
019eb63a-6ba3-710f-bc1b-b26deeaadd84
019eb63a-6ba3-7229-9e28-39508f94faad
019eb63a-6ba3-7340-ad7b-43af1ee37060
019eb63a-6ba3-7452-a2ea-2c0604e5a823
019eb63a-6ba3-7565-8e93-daa8462cbf28
019eb63a-6ba3-767b-a182-a382349441a6
019eb63a-6ba3-779a-8d5b-636bffdd7358
019eb63a-6ba3-78b1-9f88-ce5c160d3afc
019eb63a-6ba3-79c3-8752-8ed6e81cd1c9
019eb63a-6ba3-7ada-baff-2ee4028a7bdd
019eb63a-6ba3-7bec-977a-0f5e0d6c7ca8

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)

1f165805-d8df-6046-9dd6-4cf95d479851
1f165805-d8df-61d6-9dd6-4cf95d479851
1f165805-d8df-62c6-9dd6-4cf95d479851
1f165805-d8df-6398-9dd6-4cf95d479851
1f165805-d8df-6460-9dd6-4cf95d479851
1f165805-d8df-6528-9dd6-4cf95d479851
1f165805-d8df-65f0-9dd6-4cf95d479851
1f165805-d8df-66b8-9dd6-4cf95d479851
1f165805-d8df-6776-9dd6-4cf95d479851
1f165805-d8df-683e-9dd6-4cf95d479851
1f165805-d8df-6992-9dd6-4cf95d479851
1f165805-d8df-6a64-9dd6-4cf95d479851
1f165805-d8df-6b22-9dd6-4cf95d479851
1f165805-d8df-6bea-9dd6-4cf95d479851
1f165805-d8df-6cb2-9dd6-4cf95d479851

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)

5d8dfd98-6580-11f1-9dd6-4cf95d479851
5d8dfe06-6580-11f1-9dd6-4cf95d479851
5d8dfe74-6580-11f1-9dd6-4cf95d479851
5d8dfee2-6580-11f1-9dd6-4cf95d479851
5d8dff46-6580-11f1-9dd6-4cf95d479851
5d8dffaa-6580-11f1-9dd6-4cf95d479851
5d8e0018-6580-11f1-9dd6-4cf95d479851
5d8e0086-6580-11f1-9dd6-4cf95d479851
5d8e00ea-6580-11f1-9dd6-4cf95d479851
5d8e0158-6580-11f1-9dd6-4cf95d479851
5d8e01bc-6580-11f1-9dd6-4cf95d479851
5d8e0220-6580-11f1-9dd6-4cf95d479851
5d8e028e-6580-11f1-9dd6-4cf95d479851
5d8e02f2-6580-11f1-9dd6-4cf95d479851
5d8e0356-6580-11f1-9dd6-4cf95d479851

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)

70da8002-7602-820a-87ea-5ce32bd83b97
6c408102-7602-820a-87ea-5ce32bd83b97
ce0d8202-7602-820a-87ea-5ce32bd83b97
71808302-7602-820a-87ea-5ce32bd83b97
6daa8402-7602-820a-87ea-5ce32bd83b97
9d2b8502-7602-820a-87ea-5ce32bd83b97
4e5d8602-7602-820a-87ea-5ce32bd83b97
c4948702-7602-820a-87ea-5ce32bd83b97
d72c8802-7602-820a-87ea-5ce32bd83b97
a48a8902-7602-820a-87ea-5ce32bd83b97
0dd28a02-7602-820a-87ea-5ce32bd83b97
5cc28b02-7602-820a-87ea-5ce32bd83b97
dc5d8c02-7602-820a-87ea-5ce32bd83b97
84d98d02-7602-820a-87ea-5ce32bd83b97
80aa8e02-7602-820a-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)

9b86787e-731a-4787-bb63-152b4533fceb
3b00a522-d52a-4b2b-802d-6cae4afa0178
c8cbce86-d7d7-4031-9387-6384652e4b38
f2cd97d8-e0ce-497f-a9dd-85bcc62413b0
dfececf9-2b57-4790-8d5a-a84460547229
c5bee649-8839-48cf-82fb-dc6733879efa
236c393d-de79-4667-bdc1-756fc98a5d95
0f1a65fa-cf49-44c4-b7f0-619d044f6a5f
aac6afe3-8fe5-45c6-a65d-a4726b88d2cf
b3a24cdd-6d9e-4f45-9fee-5428f2c2eec0
d8b13483-f102-4b57-95a2-5200aa52ce6a
6e28e08f-83a2-42a3-bc6f-86e03289223b
88cafe83-6160-436f-a40a-63c0fe92a50b
1bed0920-8be1-4292-8988-3f332a937f05
ae1cffd8-5dac-4920-a1a1-66149a354dea

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: