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)

019ccba9-fd8e-7138-86c5-50c98d3152b9
019ccba9-fd8e-7340-8865-2a1af1bdf319
019ccba9-fd8e-7494-8c8d-e732cdf4e36b
019ccba9-fd8e-75b7-b314-1ec114e32212
019ccba9-fd8e-76d1-b337-3456bf185fe7
019ccba9-fd8e-77f4-b8fa-c89c5ddca33c
019ccba9-fd8e-790f-b19e-af9cce5c35ba
019ccba9-fd8e-7a2e-8305-aa2ec1ca4ce5
019ccba9-fd8e-7b48-8692-75ee9011ec29
019ccba9-fd8e-7c63-b14d-76dbd544cf9b
019ccba9-fd8e-7d7d-a398-ca380f536d30
019ccba9-fd8e-7e15-935f-c68abe6c5aa0
019ccba9-fd8e-7f3c-89a4-ed84a3f7e1c8
019ccba9-fd8f-705b-a25e-d39a3acd9ed1
019ccba9-fd8f-7175-91bd-726bdaa5c15b

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)

1f11aa5b-3c1e-69b6-8294-4cf95d479851
1f11aa5b-3c1e-6baa-8294-4cf95d479851
1f11aa5b-3c1e-6c86-8294-4cf95d479851
1f11aa5b-3c1e-6d4e-8294-4cf95d479851
1f11aa5b-3c1e-6e0c-8294-4cf95d479851
1f11aa5b-3c1e-6ec0-8294-4cf95d479851
1f11aa5b-3c1e-6f7e-8294-4cf95d479851
1f11aa5b-3c1f-6032-8294-4cf95d479851
1f11aa5b-3c1f-60e6-8294-4cf95d479851
1f11aa5b-3c1f-61a4-8294-4cf95d479851
1f11aa5b-3c1f-62e4-8294-4cf95d479851
1f11aa5b-3c1f-63ac-8294-4cf95d479851
1f11aa5b-3c1f-6460-8294-4cf95d479851
1f11aa5b-3c1f-6514-8294-4cf95d479851
1f11aa5b-3c1f-65d2-8294-4cf95d479851

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)

fb5f62e7-6273-4c3c-b937-0206f4d6349c
bf7c6559-3c45-465e-828b-456017c7c113
4e6fc0fe-d7eb-4767-b3c8-fc27e94a5421
38c0c362-f940-47bf-965b-fe0e65ff366b
5e2095f7-6d2c-48f4-b2e4-0b0a27cb0f20
077eabbe-c1dc-4003-be07-1f28ce3b59a5
3a33d256-6ed4-43d2-9ae9-fac4d9b01df6
1a60f80e-28c6-4448-ba91-5ee4411c7c7e
f0aab6ac-9cd7-49b1-99ba-d9901a6c6390
f66b7551-53bf-4aeb-aa1e-72f401dc9505
00e3a87c-0636-45c6-b87f-d5fa1f54cd17
ca5716c4-3843-4582-afbf-30b7ec97a010
978021b0-9f91-46ec-9743-78d651eef217
308a9926-e5b0-4c31-b361-529aec2d3329
c577fb83-98d8-44a4-b2ac-475805a4db7b

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)

b3c1fbcc-1aa5-11f1-8294-4cf95d479851
b3c1fc30-1aa5-11f1-8294-4cf95d479851
b3c1fc8a-1aa5-11f1-8294-4cf95d479851
b3c1fce4-1aa5-11f1-8294-4cf95d479851
b3c1fd3e-1aa5-11f1-8294-4cf95d479851
b3c1fd98-1aa5-11f1-8294-4cf95d479851
b3c1fdf2-1aa5-11f1-8294-4cf95d479851
b3c1fe56-1aa5-11f1-8294-4cf95d479851
b3c1feb0-1aa5-11f1-8294-4cf95d479851
b3c1ff0a-1aa5-11f1-8294-4cf95d479851
b3c1ff64-1aa5-11f1-8294-4cf95d479851
b3c1ffbe-1aa5-11f1-8294-4cf95d479851
b3c20018-1aa5-11f1-8294-4cf95d479851
b3c2007c-1aa5-11f1-8294-4cf95d479851
b3c200d6-1aa5-11f1-8294-4cf95d479851

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)

dbb44b15-0201-8304-87ea-5ce32bd83b97
2f934d15-0201-8304-87ea-5ce32bd83b97
e9304e15-0201-8304-87ea-5ce32bd83b97
0c5d4f15-0201-8304-87ea-5ce32bd83b97
3e255015-0201-8304-87ea-5ce32bd83b97
33d75115-0201-8304-87ea-5ce32bd83b97
fcb65215-0201-8304-87ea-5ce32bd83b97
5beb5315-0201-8304-87ea-5ce32bd83b97
f0d55415-0201-8304-87ea-5ce32bd83b97
34025515-0201-8304-87ea-5ce32bd83b97
095e5615-0201-8304-87ea-5ce32bd83b97
52e85715-0201-8304-87ea-5ce32bd83b97
3c9a5815-0201-8304-87ea-5ce32bd83b97
51705915-0201-8304-87ea-5ce32bd83b97
c5875a15-0201-8304-87ea-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: