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)

01984bef-7905-779e-b8cd-7739469279a0
01984bef-7905-7950-8fd9-b069c324e1ba
01984bef-7905-7abd-b063-8054ba747e68
01984bef-7905-7be4-8b78-70f9f7bee19a
01984bef-7905-7d03-94e1-360fb31edffa
01984bef-7905-7e1d-b605-2138c28e5007
01984bef-7905-7f34-ba85-c3e75ca875eb
01984bef-7906-704e-bc1a-847335eb3033
01984bef-7906-7169-8054-6f6fe1d9713a
01984bef-7906-7284-9328-368ab1719cea
01984bef-7906-739e-b287-b0769a448509
01984bef-7906-74b5-9ea2-0ade96728fd1
01984bef-7906-75cf-9b1f-973cab6704c8
01984bef-7906-76e6-9889-1f66593d4361
01984bef-7906-7800-a4e6-9190f8eed6b9

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)

1f06ae84-de8d-6338-8ba0-4cf95d479851
1f06ae84-de8d-64dc-8ba0-4cf95d479851
1f06ae84-de8d-65c2-8ba0-4cf95d479851
1f06ae84-de8d-668a-8ba0-4cf95d479851
1f06ae84-de8d-6752-8ba0-4cf95d479851
1f06ae84-de8d-6810-8ba0-4cf95d479851
1f06ae84-de8d-68ce-8ba0-4cf95d479851
1f06ae84-de8d-698c-8ba0-4cf95d479851
1f06ae84-de8d-6a4a-8ba0-4cf95d479851
1f06ae84-de8d-6b08-8ba0-4cf95d479851
1f06ae84-de8d-6c48-8ba0-4cf95d479851
1f06ae84-de8d-6d1a-8ba0-4cf95d479851
1f06ae84-de8d-6dd8-8ba0-4cf95d479851
1f06ae84-de8d-6e8c-8ba0-4cf95d479851
1f06ae84-de8d-6f54-8ba0-4cf95d479851

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)

c5d100c8-24f1-41f0-8607-89a7640099f5
dd40d8dd-9a97-4cce-8170-b6014788ab1b
236a7a4c-8d2d-4130-bb84-ce0d08158f46
1558326f-b58b-4628-824d-6cd35c2d369e
d8c9a382-2b95-433a-9191-1977d6a23324
d08d5dda-dc3b-419c-a220-fd8173ba80d8
e2a25191-7f88-4e60-9cd7-60bdfad1274c
4ccf5c5c-f96f-4fde-bad6-73c0b47ab46d
5d7a9f23-1813-4d1e-a2fa-5cef944ebd43
dad2805b-42fd-4fe2-a70a-4dbfd772b2ff
91e8a968-4df7-4718-806b-181c33447d57
117255f3-20d1-4411-9c48-a2eee443875e
449ff82a-0783-46f8-ab16-90509e133cf7
43f80da0-a794-48f9-9f02-6aae3218292e
f39fd775-2919-46b2-baa9-746eed28512b

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)

4de8e468-6ae8-11f0-8ba0-4cf95d479851
4de8e4cc-6ae8-11f0-8ba0-4cf95d479851
4de8e530-6ae8-11f0-8ba0-4cf95d479851
4de8e594-6ae8-11f0-8ba0-4cf95d479851
4de8e602-6ae8-11f0-8ba0-4cf95d479851
4de8e666-6ae8-11f0-8ba0-4cf95d479851
4de8e6ca-6ae8-11f0-8ba0-4cf95d479851
4de8e72e-6ae8-11f0-8ba0-4cf95d479851
4de8e79c-6ae8-11f0-8ba0-4cf95d479851
4de8e800-6ae8-11f0-8ba0-4cf95d479851
4de8e85a-6ae8-11f0-8ba0-4cf95d479851
4de8e8c8-6ae8-11f0-8ba0-4cf95d479851
4de8e922-6ae8-11f0-8ba0-4cf95d479851
4de8e986-6ae8-11f0-8ba0-4cf95d479851
4de8e9ea-6ae8-11f0-8ba0-4cf95d479851

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)

66ee0e2a-0303-800d-87e9-5ce32bd83b97
8a970f2a-0303-800d-87e9-5ce32bd83b97
18e4102a-0303-800d-87e9-5ce32bd83b97
5bdf112a-0303-800d-87e9-5ce32bd83b97
99fe122a-0303-800d-87e9-5ce32bd83b97
6e87132a-0303-800d-87e9-5ce32bd83b97
c8f2142a-0303-800d-87e9-5ce32bd83b97
de4e152a-0303-800d-87e9-5ce32bd83b97
406f162a-0303-800d-87e9-5ce32bd83b97
8f15172a-0303-800d-87e9-5ce32bd83b97
0e82192a-0303-800d-87e9-5ce32bd83b97
d1a21a2a-0303-800d-87e9-5ce32bd83b97
8fb41b2a-0303-800d-87e9-5ce32bd83b97
d80d1c2a-0303-800d-87e9-5ce32bd83b97
64441d2a-0303-800d-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: