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)

019b7b65-a74b-7569-b1f1-3bbc48cbd862
019b7b65-a74b-7857-b2d7-e49ad3cfe266
019b7b65-a74b-79bb-bc96-7114868b4294
019b7b65-a74b-7ade-86d6-e37f09a81edc
019b7b65-a74b-7bfc-88e3-5ad914134e8f
019b7b65-a74b-7d17-8dec-e07fa96b597a
019b7b65-a74b-7e32-8ec2-1f2e0b15a7a1
019b7b65-a74b-7f4c-aea1-357c2b3123a4
019b7b65-a74c-7073-97cf-28e7f384ee46
019b7b65-a74c-7196-a3e7-806b1b11183c
019b7b65-a74c-72b5-884a-af6c31c88d5a
019b7b65-a74c-73cf-beee-030305cb4c65
019b7b65-a74c-74ee-9f84-a00245f8632e
019b7b65-a74c-7605-ae16-cdc6f68b1721
019b7b65-a74c-771f-85fb-e7659c0d4faf

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)

1f0e7564-6585-6e50-a9e5-4cf95d479851
1f0e7564-6586-603a-a9e5-4cf95d479851
1f0e7564-6586-6134-a9e5-4cf95d479851
1f0e7564-6586-6206-a9e5-4cf95d479851
1f0e7564-6586-62e2-a9e5-4cf95d479851
1f0e7564-6586-63be-a9e5-4cf95d479851
1f0e7564-6586-6490-a9e5-4cf95d479851
1f0e7564-6586-6562-a9e5-4cf95d479851
1f0e7564-6586-662a-a9e5-4cf95d479851
1f0e7564-6586-66fc-a9e5-4cf95d479851
1f0e7564-6586-688c-a9e5-4cf95d479851
1f0e7564-6586-6968-a9e5-4cf95d479851
1f0e7564-6586-6a3a-a9e5-4cf95d479851
1f0e7564-6586-6b0c-a9e5-4cf95d479851
1f0e7564-6586-6bd4-a9e5-4cf95d479851

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)

0bdf83eb-c288-4a12-a8fb-efe44516c086
7a669480-2c39-48b3-970d-902dbf15bc4a
3812e09b-b177-43fa-a96f-caa5aec371b7
9f4012be-ce1a-4d5d-83b9-c1dcb6747a94
a0dd01ef-2c2c-481a-82ad-ebe4bb39c549
721bb5bf-7120-4053-9ffa-51c1839fe49f
61ac5e4f-d6bb-4754-88ff-76b2d369054d
dc869176-f696-4bb0-9429-dac13882a294
5ce4aff1-0984-4809-9a00-46d878b470b8
0e2fb1d2-7f42-48dd-9332-58aa88b406fc
f640ed2a-13c0-4596-ab96-b2402ffc6b9d
ddf9f5c6-5795-4eca-b6d0-f289cbcfbd0a
159f8187-4d5a-4dcf-8cb3-0ccad3d4d47f
a732ded9-ca06-4f8a-8bd7-9cf5886e7862
a89454c9-0c1f-4754-9bac-8bcae1c3959b

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)

4658711a-e756-11f0-a9e5-4cf95d479851
46587188-e756-11f0-a9e5-4cf95d479851
465871f6-e756-11f0-a9e5-4cf95d479851
46587264-e756-11f0-a9e5-4cf95d479851
465872c8-e756-11f0-a9e5-4cf95d479851
46587336-e756-11f0-a9e5-4cf95d479851
465873a4-e756-11f0-a9e5-4cf95d479851
46587408-e756-11f0-a9e5-4cf95d479851
46587476-e756-11f0-a9e5-4cf95d479851
465874da-e756-11f0-a9e5-4cf95d479851
4658753e-e756-11f0-a9e5-4cf95d479851
465875a2-e756-11f0-a9e5-4cf95d479851
465875fc-e756-11f0-a9e5-4cf95d479851
46587660-e756-11f0-a9e5-4cf95d479851
465876ce-e756-11f0-a9e5-4cf95d479851

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)

99e53012-f704-8100-87ea-5ce32bd83b97
31303112-f704-8100-87ea-5ce32bd83b97
76f23212-f704-8100-87ea-5ce32bd83b97
9de93312-f704-8100-87ea-5ce32bd83b97
8a9a3412-f704-8100-87ea-5ce32bd83b97
a3fb3512-f704-8100-87ea-5ce32bd83b97
40b13612-f704-8100-87ea-5ce32bd83b97
516d3712-f704-8100-87ea-5ce32bd83b97
c4203812-f704-8100-87ea-5ce32bd83b97
f4493912-f704-8100-87ea-5ce32bd83b97
b3953a12-f704-8100-87ea-5ce32bd83b97
5bd83c12-f704-8100-87ea-5ce32bd83b97
254a3d12-f704-8100-87ea-5ce32bd83b97
a5473e12-f704-8100-87ea-5ce32bd83b97
400a3f12-f704-8100-87ea-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: