UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019f515c-1ab6-74fa-b4d8-4f372aed6ce0
019f515c-1ab6-768c-8f22-7bf636a36897
019f515c-1ab6-77ec-b83c-b8f1c5f6cc4b
019f515c-1ab6-7917-89cd-fd6ebad58fb2
019f515c-1ab6-7a32-ab6e-a53699635a47
019f515c-1ab6-7b48-a241-9c15dc445314
019f515c-1ab6-7c5f-a474-a4bd0dce850a
019f515c-1ab6-7d75-8c5d-01377f374765
019f515c-1ab6-7e8c-aebd-af8ca398afaf
019f515c-1ab6-7f9e-9ee7-bae9c6483aae
019f515c-1ab7-70b5-b17f-4721af42d99b
019f515c-1ab7-71cb-b561-dd3347ec47b1
019f515c-1ab7-72e2-afec-aaa58f6145af
019f515c-1ab7-73f8-9371-72cbbe38b259
019f515c-1ab7-750f-ba49-dd8b7c4f4dcc

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)

1f17d2c3-154d-6cce-903a-4cf95d479851
1f17d2c3-154d-6e86-903a-4cf95d479851
1f17d2c3-154d-6f62-903a-4cf95d479851
1f17d2c3-154e-6034-903a-4cf95d479851
1f17d2c3-154e-60fc-903a-4cf95d479851
1f17d2c3-154e-61ba-903a-4cf95d479851
1f17d2c3-154e-6278-903a-4cf95d479851
1f17d2c3-154e-6340-903a-4cf95d479851
1f17d2c3-154e-63fe-903a-4cf95d479851
1f17d2c3-154e-64bc-903a-4cf95d479851
1f17d2c3-154e-65fc-903a-4cf95d479851
1f17d2c3-154e-66ce-903a-4cf95d479851
1f17d2c3-154e-6796-903a-4cf95d479851
1f17d2c3-154e-6854-903a-4cf95d479851
1f17d2c3-154e-691c-903a-4cf95d479851

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)

3154e9f8-7d2c-11f1-903a-4cf95d479851
3154ea5c-7d2c-11f1-903a-4cf95d479851
3154eac0-7d2c-11f1-903a-4cf95d479851
3154eb1a-7d2c-11f1-903a-4cf95d479851
3154eb7e-7d2c-11f1-903a-4cf95d479851
3154ebe2-7d2c-11f1-903a-4cf95d479851
3154ec3c-7d2c-11f1-903a-4cf95d479851
3154eca0-7d2c-11f1-903a-4cf95d479851
3154ecfa-7d2c-11f1-903a-4cf95d479851
3154ed5e-7d2c-11f1-903a-4cf95d479851
3154edc2-7d2c-11f1-903a-4cf95d479851
3154ee1c-7d2c-11f1-903a-4cf95d479851
3154ee80-7d2c-11f1-903a-4cf95d479851
3154eee4-7d2c-11f1-903a-4cf95d479851
3154ef52-7d2c-11f1-903a-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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

c24f7c3a-2703-800c-87ea-5ce32bd83b97
37567e3a-2703-800c-87ea-5ce32bd83b97
241d7f3a-2703-800c-87ea-5ce32bd83b97
2a12803a-2703-800c-87ea-5ce32bd83b97
a8f2813a-2703-800c-87ea-5ce32bd83b97
a782823a-2703-800c-87ea-5ce32bd83b97
7a15833a-2703-800c-87ea-5ce32bd83b97
cd9d843a-2703-800c-87ea-5ce32bd83b97
8a46853a-2703-800c-87ea-5ce32bd83b97
dd3e863a-2703-800c-87ea-5ce32bd83b97
6d4e873a-2703-800c-87ea-5ce32bd83b97
103c883a-2703-800c-87ea-5ce32bd83b97
2442893a-2703-800c-87ea-5ce32bd83b97
49258a3a-2703-800c-87ea-5ce32bd83b97
f4338b3a-2703-800c-87ea-5ce32bd83b97

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)

cc403b6b-8f34-4688-b505-bd595db9e336
91655ad5-54a3-4197-a1a3-b73a441a0d2e
5152c4fc-29ab-4ecb-827b-9a53faad704e
926522ad-dc7d-4e68-86fd-92ed65ee9a6b
0c492c0c-4bd4-4d5e-bdb2-4770d97705d2
3f32221c-23eb-49b3-8f46-552711a56c15
8cab5354-dd6e-4b87-b88e-e76ab0bfe716
a2a79633-0d88-4644-98af-51b3df15f16d
18cb74e6-83eb-4190-8173-c7234e92df5a
d69324d1-41bd-45e8-8c57-f71bbccc3af8
cbce229f-f317-49dc-b931-6e68d2e46d79
16264547-90df-4188-bae4-cd1677fec7c2
154fca26-425b-40ab-be5c-d7d189d9cc24
6e36d7e7-d05f-4250-b304-20123e5337ab
0ccad7f1-f56e-4ee0-b962-12b7801b2095

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: