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)

019d06c6-396f-71b3-8a0f-857c5280fc4a
019d06c6-396f-7348-a59b-2a261e1ca46e
019d06c6-396f-74cd-b410-eda94c8b42d8
019d06c6-396f-7609-86d1-81f60c2ee735
019d06c6-396f-7723-ac90-cf436a2aac28
019d06c6-396f-783e-b720-a20e73d6c668
019d06c6-396f-79b3-b435-01647a6105fd
019d06c6-396f-7b07-95d3-b4dbcaac2cd1
019d06c6-396f-7c3e-acf3-15d1d8407866
019d06c6-396f-7d8a-bd26-17deb0343a56
019d06c6-396f-7ecd-b0e3-d5c3e4f1f11d
019d06c6-396f-7009-a6b1-672fb2830aea
019d06c6-3972-7211-a255-9c4afdfceb64
019d06c6-3972-7365-9cb9-ff95e1a78d70
019d06c6-3972-7488-b0a5-963620117e6e

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)

1f123aab-2a54-6466-aec2-4cf95d479851
1f123aab-2a54-6614-aec2-4cf95d479851
1f123aab-2a54-670e-aec2-4cf95d479851
1f123aab-2a54-67ea-aec2-4cf95d479851
1f123aab-2a54-68b2-aec2-4cf95d479851
1f123aab-2a54-6984-aec2-4cf95d479851
1f123aab-2a54-6a56-aec2-4cf95d479851
1f123aab-2a54-6b1e-aec2-4cf95d479851
1f123aab-2a54-6bf0-aec2-4cf95d479851
1f123aab-2a54-6cb8-aec2-4cf95d479851
1f123aab-2a54-6e16-aec2-4cf95d479851
1f123aab-2a54-6ef2-aec2-4cf95d479851
1f123aab-2a54-6fba-aec2-4cf95d479851
1f123aab-2a55-608c-aec2-4cf95d479851
1f123aab-2a55-615e-aec2-4cf95d479851

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)

68d857dd-f577-433b-9ba2-4bc40b3c3a2e
090078ff-f010-4b60-b46b-51ed62010614
8ab2928c-cfb6-4e09-844d-70e5a2efaf82
7b6f0931-00b8-4dbf-aed8-54d745ac0034
7f5e4c2c-6feb-4d73-a30e-2ed794d1d75e
19174d25-ba96-4dba-8db2-2828df2fea56
5c70a43a-7cf3-47f1-a378-42806ed5b9ca
ee34272e-6adb-44f2-919f-17f043e22886
a21fecb1-6b66-42a7-8ace-f3dd07f13c5a
c9487089-5f29-4d50-966e-608078fada9e
50339802-a678-45e0-9b25-f1cf540bd59b
bf7073ae-7081-406b-97e5-de3e3b90a77e
06679d69-8492-4de4-adec-5aeea622f5c7
ed4024aa-017e-4a08-acb5-4325179cb748
2996fb79-00be-4675-9e97-7c77f65eadfc

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)

b2a5569a-23aa-11f1-aec2-4cf95d479851
b2a556fe-23aa-11f1-aec2-4cf95d479851
b2a55762-23aa-11f1-aec2-4cf95d479851
b2a557c6-23aa-11f1-aec2-4cf95d479851
b2a5582a-23aa-11f1-aec2-4cf95d479851
b2a5588e-23aa-11f1-aec2-4cf95d479851
b2a558f2-23aa-11f1-aec2-4cf95d479851
b2a55956-23aa-11f1-aec2-4cf95d479851
b2a559c4-23aa-11f1-aec2-4cf95d479851
b2a55a28-23aa-11f1-aec2-4cf95d479851
b2a55a8c-23aa-11f1-aec2-4cf95d479851
b2a55afa-23aa-11f1-aec2-4cf95d479851
b2a55b7c-23aa-11f1-aec2-4cf95d479851
b2a55bf4-23aa-11f1-aec2-4cf95d479851
b2a55c62-23aa-11f1-aec2-4cf95d479851

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)

cdac612f-b203-8e04-87ea-5ce32bd83b97
399b622f-b203-8e04-87ea-5ce32bd83b97
7b41632f-b203-8e04-87ea-5ce32bd83b97
eba8642f-b203-8e04-87ea-5ce32bd83b97
682a652f-b203-8e04-87ea-5ce32bd83b97
acc3662f-b203-8e04-87ea-5ce32bd83b97
e52b672f-b203-8e04-87ea-5ce32bd83b97
91d0682f-b203-8e04-87ea-5ce32bd83b97
8107692f-b203-8e04-87ea-5ce32bd83b97
2ccd6a2f-b203-8e04-87ea-5ce32bd83b97
3a866b2f-b203-8e04-87ea-5ce32bd83b97
2fc06c2f-b203-8e04-87ea-5ce32bd83b97
b6706d2f-b203-8e04-87ea-5ce32bd83b97
93346e2f-b203-8e04-87ea-5ce32bd83b97
b5ae6f2f-b203-8e04-87ea-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: