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)

019de91c-48b0-79e8-9c04-2ff984dc9f3d
019de91c-48b0-7bc7-b2eb-6f671e515b43
019de91c-48b0-7d54-bcff-2d9f20952a09
019de91c-48b0-7eb9-811d-51149ba2b8cb
019de91c-48b0-7009-bcf6-4b1e6c2d1015
019de91c-48b1-715d-b5df-49103a4daff4
019de91c-48b1-72a8-91df-5a96bb3fc075
019de91c-48b1-73ec-992e-4bc0b6d5ccf5
019de91c-48b1-7534-8fe6-7c814a756396
019de91c-48b1-767b-b6d3-46921bfa6589
019de91c-48b1-77a6-82ef-591a378f32fb
019de91c-48b1-78d5-be72-3a1cf0c18f7d
019de91c-48b1-7a4a-b439-bcbf927a2317
019de91c-48b1-7b5d-a336-4d7bf77781f3
019de91c-48b1-7ea8-8623-539f3a4de500

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)

1f14633f-458e-6ace-85f6-4cf95d479851
1f14633f-458e-6d26-85f6-4cf95d479851
1f14633f-458e-6e84-85f6-4cf95d479851
1f14633f-458e-6fc4-85f6-4cf95d479851
1f14633f-458f-60e6-85f6-4cf95d479851
1f14633f-458f-6230-85f6-4cf95d479851
1f14633f-458f-6370-85f6-4cf95d479851
1f14633f-458f-64b0-85f6-4cf95d479851
1f14633f-458f-65f0-85f6-4cf95d479851
1f14633f-458f-673a-85f6-4cf95d479851
1f14633f-458f-691a-85f6-4cf95d479851
1f14633f-458f-6a6e-85f6-4cf95d479851
1f14633f-458f-6bc2-85f6-4cf95d479851
1f14633f-458f-6d0c-85f6-4cf95d479851
1f14633f-458f-6e6a-85f6-4cf95d479851

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)

eec61a30-c909-416a-be30-d6bfd77ea8df
db3b5f78-8cfd-4f32-b0ec-ad4feb360a3e
8e8e0e1f-3f93-4fa8-8fd8-36e6815da4fe
80e0437f-9be0-4a91-9a60-42d8d945f8f7
7157e97b-ed62-47be-b1ab-06f87e12ed48
6b2acec4-8b74-43b1-a1b6-293738dc55ec
6a11b75e-364e-4c4f-aa55-7c0f3bdecfc3
7a511277-8d2e-429f-9468-bb4fada54767
883b4fe9-4a56-4b40-a710-ef1cc04fed5f
f07a1c74-5b4d-48c6-9b50-2b861633f416
cdba116b-355e-4409-ad21-d6aa51c0ad1c
f6ff4097-0b0b-4f3b-859e-5ae28f2f3750
b88b0b2f-ac4d-413c-bac4-9b63dfec1fe0
c1b84e98-3009-49cc-95fa-27bdda1283b9
724bd1a7-3be5-4668-9825-923d498ec8a9

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)

f4590572-4633-11f1-85f6-4cf95d479851
f459061c-4633-11f1-85f6-4cf95d479851
f45906bc-4633-11f1-85f6-4cf95d479851
f459075c-4633-11f1-85f6-4cf95d479851
f45907e8-4633-11f1-85f6-4cf95d479851
f459087e-4633-11f1-85f6-4cf95d479851
f459090a-4633-11f1-85f6-4cf95d479851
f4590996-4633-11f1-85f6-4cf95d479851
f4590a2c-4633-11f1-85f6-4cf95d479851
f4590ac2-4633-11f1-85f6-4cf95d479851
f4590b58-4633-11f1-85f6-4cf95d479851
f4590be4-4633-11f1-85f6-4cf95d479851
f4590c84-4633-11f1-85f6-4cf95d479851
f4590d10-4633-11f1-85f6-4cf95d479851
f4590d9c-4633-11f1-85f6-4cf95d479851

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)

04bc323a-6a03-8a07-87ea-5ce32bd83b97
3c6c333a-6a03-8a07-87ea-5ce32bd83b97
c067343a-6a03-8a07-87ea-5ce32bd83b97
b249353a-6a03-8a07-87ea-5ce32bd83b97
9e86363a-6a03-8a07-87ea-5ce32bd83b97
17c9373a-6a03-8a07-87ea-5ce32bd83b97
7c5a383a-6a03-8a07-87ea-5ce32bd83b97
4145393a-6a03-8a07-87ea-5ce32bd83b97
ed4e3a3a-6a03-8a07-87ea-5ce32bd83b97
36e33b3a-6a03-8a07-87ea-5ce32bd83b97
b0083c3a-6a03-8a07-87ea-5ce32bd83b97
6f0d3d3a-6a03-8a07-87ea-5ce32bd83b97
12a53e3a-6a03-8a07-87ea-5ce32bd83b97
c79a3f3a-6a03-8a07-87ea-5ce32bd83b97
5379403a-6a03-8a07-87ea-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: