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)

019fc26c-9208-7cd5-aa89-04602f2b0f2b
019fc26c-9208-7e73-b06c-8694046b3c58
019fc26c-9208-7faa-9885-5f25cc21d4cd
019fc26c-9209-70c5-811b-d91726494fb4
019fc26c-9209-71dc-8968-46be46656357
019fc26c-9209-72f2-b8d1-12bdbe04c2e7
019fc26c-9209-7405-8dd3-9d5b1f8d4c0c
019fc26c-9209-751b-a116-45c7af874c22
019fc26c-9209-762e-b0ab-56d44aefed11
019fc26c-9209-7744-bf62-d42499fdf318
019fc26c-9209-785b-88c2-2c1cff42dfef
019fc26c-9209-7971-a97b-1f6b8b20a643
019fc26c-9209-7a88-b500-cf130c6cacd7
019fc26c-9209-7ba6-88cd-e63be3b70a38
019fc26c-9209-7cbd-9324-b697bea219d3

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)

1f18e6cc-489e-63ee-8db5-4cf95d479851
1f18e6cc-489e-6588-8db5-4cf95d479851
1f18e6cc-489e-666e-8db5-4cf95d479851
1f18e6cc-489e-6736-8db5-4cf95d479851
1f18e6cc-489e-67f4-8db5-4cf95d479851
1f18e6cc-489e-68bc-8db5-4cf95d479851
1f18e6cc-489e-697a-8db5-4cf95d479851
1f18e6cc-489e-6a38-8db5-4cf95d479851
1f18e6cc-489e-6af6-8db5-4cf95d479851
1f18e6cc-489e-6bb4-8db5-4cf95d479851
1f18e6cc-489e-6cea-8db5-4cf95d479851
1f18e6cc-489e-6dbc-8db5-4cf95d479851
1f18e6cc-489e-6e7a-8db5-4cf95d479851
1f18e6cc-489e-6f38-8db5-4cf95d479851
1f18e6cc-489e-6ff6-8db5-4cf95d479851

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)

c489f0be-8e6c-11f1-8db5-4cf95d479851
c489f12c-8e6c-11f1-8db5-4cf95d479851
c489f190-8e6c-11f1-8db5-4cf95d479851
c489f1f4-8e6c-11f1-8db5-4cf95d479851
c489f24e-8e6c-11f1-8db5-4cf95d479851
c489f2b2-8e6c-11f1-8db5-4cf95d479851
c489f316-8e6c-11f1-8db5-4cf95d479851
c489f37a-8e6c-11f1-8db5-4cf95d479851
c489f3d4-8e6c-11f1-8db5-4cf95d479851
c489f438-8e6c-11f1-8db5-4cf95d479851
c489f492-8e6c-11f1-8db5-4cf95d479851
c489f500-8e6c-11f1-8db5-4cf95d479851
c489f55a-8e6c-11f1-8db5-4cf95d479851
c489f5b4-8e6c-11f1-8db5-4cf95d479851
c489f618-8e6c-11f1-8db5-4cf95d479851

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)

44740503-e702-860d-87ea-5ce32bd83b97
e5200603-e702-860d-87ea-5ce32bd83b97
a70d0703-e702-860d-87ea-5ce32bd83b97
ecc70803-e702-860d-87ea-5ce32bd83b97
91e00903-e702-860d-87ea-5ce32bd83b97
4b400a03-e702-860d-87ea-5ce32bd83b97
101a0b03-e702-860d-87ea-5ce32bd83b97
03070c03-e702-860d-87ea-5ce32bd83b97
5e2d0d03-e702-860d-87ea-5ce32bd83b97
43d30e03-e702-860d-87ea-5ce32bd83b97
d1bd0f03-e702-860d-87ea-5ce32bd83b97
ba231003-e702-860d-87ea-5ce32bd83b97
98781103-e702-860d-87ea-5ce32bd83b97
008b1203-e702-860d-87ea-5ce32bd83b97
03f61303-e702-860d-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)

d2fe9220-e1ef-4a2d-a426-5947b4befedd
52c274be-afbc-47df-87e0-b4cd69999567
4b26cd35-be3e-405a-af91-eeb218ac02b0
09a66649-c2a8-4344-a983-09fd0c1abbb6
45205a82-7650-459b-9ef7-f67c707489f5
9206c4a2-8778-42f6-9744-7168081fcce3
01ebb8f6-169e-4eb8-9979-ff459aea8e9e
025cbbb0-90e2-4cd0-acbe-a4489f5f0ff4
23705e21-603b-4a00-bf2e-b94ac79d4c50
d8791900-5344-419d-b45b-5ec10949beb3
bab9c366-54d5-4f77-bd06-9bc0c973e6b4
fbd19616-1124-4560-bd71-10c21b4f4890
671bd2d1-8793-45fd-9670-21db3cc7c408
8bc9ab1b-6920-4d0d-a243-872691af3d1a
fe12d429-1bc6-4e4c-a585-02ca5895da50

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: