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)

01a199c7-e8d7-7759-bf22-82b2947667a7
01a199c7-e8d7-78de-9439-f11c0912d3eb
01a199c7-e8d7-7a21-9d56-2e931d00a8bb
01a199c7-e8d7-7b44-9b51-d685571a3f71
01a199c7-e8d7-7c5f-8836-f6cfcc292b5c
01a199c7-e8d7-7d79-8d86-4e640b6af143
01a199c7-e8d7-7e90-b7a1-79ff28621d19
01a199c7-e8d7-7faa-b997-8b7b385c5deb
01a199c7-e8d8-70c5-b3ab-edda5b63aced
01a199c7-e8d8-71dc-a53c-c3e6c6ce07b8
01a199c7-e8d8-72f6-ad8f-e46e4add31ba
01a199c7-e8d8-7467-81ce-e0f419557dd7
01a199c7-e8d8-75b3-9bf5-609f775a10aa
01a199c7-e8d8-76d5-b6f9-1f11b4c22fe1
01a199c7-e8d8-77f0-b750-c34c3ade5648

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)

1f1d6592-478c-6d0e-b7ae-4cf95d479851
1f1d6592-478c-6eee-b7ae-4cf95d479851
1f1d6592-478c-6fde-b7ae-4cf95d479851
1f1d6592-478d-60b0-b7ae-4cf95d479851
1f1d6592-478d-618c-b7ae-4cf95d479851
1f1d6592-478d-6254-b7ae-4cf95d479851
1f1d6592-478d-631c-b7ae-4cf95d479851
1f1d6592-478d-63ee-b7ae-4cf95d479851
1f1d6592-478d-64c0-b7ae-4cf95d479851
1f1d6592-478d-6588-b7ae-4cf95d479851
1f1d6592-478d-66d2-b7ae-4cf95d479851
1f1d6592-478d-67b8-b7ae-4cf95d479851
1f1d6592-478d-688a-b7ae-4cf95d479851
1f1d6592-478d-6952-b7ae-4cf95d479851
1f1d6592-478d-6a24-b7ae-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)

2478db0a-d659-11f1-b7ae-4cf95d479851
2478db78-d659-11f1-b7ae-4cf95d479851
2478dbdc-d659-11f1-b7ae-4cf95d479851
2478dc4a-d659-11f1-b7ae-4cf95d479851
2478dca4-d659-11f1-b7ae-4cf95d479851
2478dd12-d659-11f1-b7ae-4cf95d479851
2478dd76-d659-11f1-b7ae-4cf95d479851
2478ddda-d659-11f1-b7ae-4cf95d479851
2478de3e-d659-11f1-b7ae-4cf95d479851
2478dea2-d659-11f1-b7ae-4cf95d479851
2478defc-d659-11f1-b7ae-4cf95d479851
2478df56-d659-11f1-b7ae-4cf95d479851
2478dfba-d659-11f1-b7ae-4cf95d479851
2478e01e-d659-11f1-b7ae-4cf95d479851
2478e082-d659-11f1-b7ae-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)

e6bec039-3f00-8213-87ea-5ce32bd83b97
ee09c139-3f00-8213-87ea-5ce32bd83b97
feeac239-3f00-8213-87ea-5ce32bd83b97
eda7c339-3f00-8213-87ea-5ce32bd83b97
41d5c439-3f00-8213-87ea-5ce32bd83b97
d735c539-3f00-8213-87ea-5ce32bd83b97
d598c639-3f00-8213-87ea-5ce32bd83b97
ce4bc739-3f00-8213-87ea-5ce32bd83b97
5b86c839-3f00-8213-87ea-5ce32bd83b97
dafec939-3f00-8213-87ea-5ce32bd83b97
286aca39-3f00-8213-87ea-5ce32bd83b97
1e12cc39-3f00-8213-87ea-5ce32bd83b97
26b5cd39-3f00-8213-87ea-5ce32bd83b97
8e9ece39-3f00-8213-87ea-5ce32bd83b97
523dcf39-3f00-8213-87ea-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)

f531cc34-64a3-465d-aeb7-505452f5c56f
11555703-8b0b-48f6-8baa-214e145e84f7
99fd2762-7528-4c6d-a7c9-015189e04a88
7a4a71d7-5b44-4ea3-9d1c-8bcfe04b4ec2
ba25184e-1bfb-4154-a11c-d38d17ee4a82
03b52914-0405-4a56-9697-17e94ba1dfa3
eb8c46bc-ddf0-4b30-9320-9cfedd04c5b8
2d88f4c4-7869-416e-8c0b-69e9a2706098
874eee48-311b-4a77-b3f1-8680bb57f67c
6088b979-1497-44bf-a3b7-8e7b9c173d10
86272118-3d05-4b98-b9d4-4715f9d7edd9
2b873060-7864-4b8b-8d30-b3eccf64a06b
3a1685f8-240f-4d76-8936-ada6fcc5c3a3
e12e7595-bcad-4aab-a897-1096501853f4
81782ea3-8cd6-493a-972e-d807fc122390

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: