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)

019cd66a-b336-76da-b788-f6d24956bf03
019cd66a-b336-786f-ad87-b9e6cbd690b8
019cd66a-b336-79aa-9330-5ee9a73b00c3
019cd66a-b336-7acd-b4e5-538d2c613b0a
019cd66a-b336-7be8-9d15-efe35d823d79
019cd66a-b336-7cfe-bbf9-3fa5f5284176
019cd66a-b336-7e25-831d-fdf07b599cad
019cd66a-b336-7f40-b524-d8db3d863cee
019cd66a-b337-705b-89f9-b3ac2840db3b
019cd66a-b337-7175-99db-0dbb2550d90f
019cd66a-b337-728c-89e0-0bd001eb6b95
019cd66a-b337-73a6-9ff1-4b33ceb37220
019cd66a-b337-74bd-95d7-bbccacf1f18b
019cd66a-b337-75d8-be1c-72cdb470b4d7
019cd66a-b337-76ee-ba28-e6b6277b2fb9

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)

1f11c49b-b79e-6938-84e5-4cf95d479851
1f11c49b-b79e-6ae6-84e5-4cf95d479851
1f11c49b-b79e-6bcc-84e5-4cf95d479851
1f11c49b-b79e-6c9e-84e5-4cf95d479851
1f11c49b-b79e-6d66-84e5-4cf95d479851
1f11c49b-b79e-6e2e-84e5-4cf95d479851
1f11c49b-b79e-6ef6-84e5-4cf95d479851
1f11c49b-b79e-6fbe-84e5-4cf95d479851
1f11c49b-b79f-6086-84e5-4cf95d479851
1f11c49b-b79f-614e-84e5-4cf95d479851
1f11c49b-b79f-62fc-84e5-4cf95d479851
1f11c49b-b79f-6464-84e5-4cf95d479851
1f11c49b-b79f-6554-84e5-4cf95d479851
1f11c49b-b79f-661c-84e5-4cf95d479851
1f11c49b-b79f-66da-84e5-4cf95d479851

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)

28910b6b-7ff6-48d1-bcc9-4e17d0631216
3c235719-6808-4e1d-89c2-4dae078ea146
9416aad6-d4ed-45eb-ae84-18ef31a09302
5798aead-425a-4c01-a200-65550670396b
7b066e87-c754-40d7-b786-462ad27bd979
d731501f-3f70-4da3-af4f-22ffea6db3f4
1c396388-4012-4d5a-9965-ad87b72f5230
22c75df9-d4eb-487f-ac59-70120fdde185
aac977b7-0e08-4069-a397-c44225cab9de
e2d09aa2-cb70-40e9-8eee-57dd3daea4af
323e7323-eff6-42f9-8c0e-ce4344feacfa
ea10c201-7407-4fa8-a84a-f7e8759f6ad4
70472cd4-84ac-4b52-a522-4c4721fa8f12
49933732-3ee7-4154-a1fb-704caad9ab3f
bcb9c6e6-936a-493c-af82-1c63ef311d47

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)

bb79fc02-1c49-11f1-84e5-4cf95d479851
bb79fc70-1c49-11f1-84e5-4cf95d479851
bb79fcd4-1c49-11f1-84e5-4cf95d479851
bb79fd38-1c49-11f1-84e5-4cf95d479851
bb79fd92-1c49-11f1-84e5-4cf95d479851
bb79fe00-1c49-11f1-84e5-4cf95d479851
bb79fe5a-1c49-11f1-84e5-4cf95d479851
bb79febe-1c49-11f1-84e5-4cf95d479851
bb79ff18-1c49-11f1-84e5-4cf95d479851
bb79ff90-1c49-11f1-84e5-4cf95d479851
bb79fff4-1c49-11f1-84e5-4cf95d479851
bb7a004e-1c49-11f1-84e5-4cf95d479851
bb7a00b2-1c49-11f1-84e5-4cf95d479851
bb7a010c-1c49-11f1-84e5-4cf95d479851
bb7a0170-1c49-11f1-84e5-4cf95d479851

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)

44d2df02-8101-8504-87ea-5ce32bd83b97
c864e002-8101-8504-87ea-5ce32bd83b97
455fe102-8101-8504-87ea-5ce32bd83b97
fd63e202-8101-8504-87ea-5ce32bd83b97
95d7e302-8101-8504-87ea-5ce32bd83b97
0f8ce402-8101-8504-87ea-5ce32bd83b97
6b7ce502-8101-8504-87ea-5ce32bd83b97
cef0e602-8101-8504-87ea-5ce32bd83b97
66bde702-8101-8504-87ea-5ce32bd83b97
ebf4e802-8101-8504-87ea-5ce32bd83b97
304ae902-8101-8504-87ea-5ce32bd83b97
045bea02-8101-8504-87ea-5ce32bd83b97
25d2eb02-8101-8504-87ea-5ce32bd83b97
45bfec02-8101-8504-87ea-5ce32bd83b97
1128ed02-8101-8504-87ea-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: