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)

019d9298-6d59-72da-9bca-47c42ab6ea10
019d9298-6d59-7494-b6c2-3e6c41fcd3fa
019d9298-6d59-75d8-a85a-735c49b86517
019d9298-6d59-76f6-a3a0-4438e5b60053
019d9298-6d59-7815-94d8-2f2b15f23254
019d9298-6d59-7934-85df-f441b4ed096d
019d9298-6d59-7a4a-b6f4-fafa22f92783
019d9298-6d59-7b65-b8af-b0b586309722
019d9298-6d59-7c7b-aab2-afb3c53e9563
019d9298-6d59-7d92-9b99-14dedbaa05b4
019d9298-6d59-7ea8-98fa-5be9287f600c
019d9298-6d59-7fc3-bb0f-72adb6b6f54b
019d9298-6d5a-70de-9f41-5d9fc40c6929
019d9298-6d5a-71f8-be3c-ac66053e2b03
019d9298-6d5a-7313-826e-9e2fa1b3a654

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)

1f139007-5b0d-6848-bfcd-4cf95d479851
1f139007-5b0d-69f6-bfcd-4cf95d479851
1f139007-5b0d-6adc-bfcd-4cf95d479851
1f139007-5b0d-6ba4-bfcd-4cf95d479851
1f139007-5b0d-6c6c-bfcd-4cf95d479851
1f139007-5b0d-6d2a-bfcd-4cf95d479851
1f139007-5b0d-6df2-bfcd-4cf95d479851
1f139007-5b0d-6eb0-bfcd-4cf95d479851
1f139007-5b0d-6f6e-bfcd-4cf95d479851
1f139007-5b0e-602c-bfcd-4cf95d479851
1f139007-5b0e-6176-bfcd-4cf95d479851
1f139007-5b0e-623e-bfcd-4cf95d479851
1f139007-5b0e-62fc-bfcd-4cf95d479851
1f139007-5b0e-63ba-bfcd-4cf95d479851
1f139007-5b0e-6478-bfcd-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)

115949be-e382-47fd-b315-686a177ba79f
37008fcf-ab44-48dd-a3c5-9520d6c65529
6cdef859-df8b-4461-9ead-b0e60e36449f
d0c68984-6028-4881-aaa6-39c7b98f08fb
b8496657-8265-4e71-ad70-d0f0c6d1adca
162920e0-4f55-4564-bd6f-60f6e71c1b91
ce4568e8-8fef-46db-92d4-55631710d721
9dfef7c7-a09d-4ef1-8954-d555adb69107
b237c9b8-9317-47cc-9772-48cd5fe1a59e
39ada408-dd18-4685-800c-7d7c70e90504
afcc5e3b-6fcf-42a9-9834-9607b4bb159c
c0853209-2199-466d-8481-e1eb267cd879
6db6024e-b595-4b22-a063-eec9d8d58577
fff49e28-aca3-4f8c-9230-fc75b57b1544
1cd2e87e-a6d0-4f33-ab10-67584bb2b495

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)

75b0e98c-3900-11f1-bfcd-4cf95d479851
75b0e9f0-3900-11f1-bfcd-4cf95d479851
75b0ea54-3900-11f1-bfcd-4cf95d479851
75b0eaae-3900-11f1-bfcd-4cf95d479851
75b0eb12-3900-11f1-bfcd-4cf95d479851
75b0eb76-3900-11f1-bfcd-4cf95d479851
75b0ebd0-3900-11f1-bfcd-4cf95d479851
75b0ec34-3900-11f1-bfcd-4cf95d479851
75b0ec98-3900-11f1-bfcd-4cf95d479851
75b0ecfc-3900-11f1-bfcd-4cf95d479851
75b0ed60-3900-11f1-bfcd-4cf95d479851
75b0edba-3900-11f1-bfcd-4cf95d479851
75b0ee1e-3900-11f1-bfcd-4cf95d479851
75b0ee78-3900-11f1-bfcd-4cf95d479851
75b0eedc-3900-11f1-bfcd-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)

f9e74024-8b04-8906-87ea-5ce32bd83b97
07bd4124-8b04-8906-87ea-5ce32bd83b97
d8374224-8b04-8906-87ea-5ce32bd83b97
086d4324-8b04-8906-87ea-5ce32bd83b97
925b4424-8b04-8906-87ea-5ce32bd83b97
a98c4524-8b04-8906-87ea-5ce32bd83b97
b5d34624-8b04-8906-87ea-5ce32bd83b97
e9ac4724-8b04-8906-87ea-5ce32bd83b97
f5dd4824-8b04-8906-87ea-5ce32bd83b97
911e4924-8b04-8906-87ea-5ce32bd83b97
2fae4a24-8b04-8906-87ea-5ce32bd83b97
743f4b24-8b04-8906-87ea-5ce32bd83b97
578c4c24-8b04-8906-87ea-5ce32bd83b97
d5544d24-8b04-8906-87ea-5ce32bd83b97
d2264f24-8b04-8906-87ea-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: