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)

01a0385a-f676-7971-9700-16f32022b718
01a0385a-f676-7b6d-b6bb-6816e26fc31c
01a0385a-f676-7cb5-a964-e4857efcaca0
01a0385a-f676-7ddc-b8db-de56e8ca8b6a
01a0385a-f676-7efe-b267-8292c1f61e2d
01a0385a-f677-7019-93da-67aabe4195d7
01a0385a-f677-713c-a227-a6354f44230b
01a0385a-f677-725b-a31a-a7807609c10e
01a0385a-f677-737d-b6d3-a3dc05e27404
01a0385a-f677-749c-9aec-531feed0ba02
01a0385a-f677-75bb-9840-481f31bb81cd
01a0385a-f677-76da-b78c-4e4b359cba8e
01a0385a-f677-77f4-b818-9a44a6248c68
01a0385a-f677-7917-87dd-497c7daf52e0
01a0385a-f677-7a36-a467-13f1ada76528

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)

1f1a06b7-4bce-6710-9c6f-4cf95d479851
1f1a06b7-4bce-68d2-9c6f-4cf95d479851
1f1a06b7-4bce-69b8-9c6f-4cf95d479851
1f1a06b7-4bce-6a94-9c6f-4cf95d479851
1f1a06b7-4bce-6b5c-9c6f-4cf95d479851
1f1a06b7-4bce-6c24-9c6f-4cf95d479851
1f1a06b7-4bce-6cec-9c6f-4cf95d479851
1f1a06b7-4bce-6db4-9c6f-4cf95d479851
1f1a06b7-4bce-6e72-9c6f-4cf95d479851
1f1a06b7-4bce-6f30-9c6f-4cf95d479851
1f1a06b7-4bcf-6070-9c6f-4cf95d479851
1f1a06b7-4bcf-6142-9c6f-4cf95d479851
1f1a06b7-4bcf-6200-9c6f-4cf95d479851
1f1a06b7-4bcf-62d2-9c6f-4cf95d479851
1f1a06b7-4bcf-63a4-9c6f-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)

74bcf476-a06b-11f1-9c6f-4cf95d479851
74bcf4ee-a06b-11f1-9c6f-4cf95d479851
74bcf55c-a06b-11f1-9c6f-4cf95d479851
74bcf5c0-a06b-11f1-9c6f-4cf95d479851
74bcf624-a06b-11f1-9c6f-4cf95d479851
74bcf692-a06b-11f1-9c6f-4cf95d479851
74bcf6f6-a06b-11f1-9c6f-4cf95d479851
74bcf75a-a06b-11f1-9c6f-4cf95d479851
74bcf7b4-a06b-11f1-9c6f-4cf95d479851
74bcf818-a06b-11f1-9c6f-4cf95d479851
74bcf872-a06b-11f1-9c6f-4cf95d479851
74bcf8e0-a06b-11f1-9c6f-4cf95d479851
74bcf944-a06b-11f1-9c6f-4cf95d479851
74bcf9a8-a06b-11f1-9c6f-4cf95d479851
74bcfa16-a06b-11f1-9c6f-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)

7b6d9100-5702-8d0e-87ea-5ce32bd83b97
0aac9200-5702-8d0e-87ea-5ce32bd83b97
53959300-5702-8d0e-87ea-5ce32bd83b97
5e529400-5702-8d0e-87ea-5ce32bd83b97
e0cd9500-5702-8d0e-87ea-5ce32bd83b97
b9e59600-5702-8d0e-87ea-5ce32bd83b97
0c299700-5702-8d0e-87ea-5ce32bd83b97
a98e9800-5702-8d0e-87ea-5ce32bd83b97
0fe79900-5702-8d0e-87ea-5ce32bd83b97
0eb09a00-5702-8d0e-87ea-5ce32bd83b97
e4909b00-5702-8d0e-87ea-5ce32bd83b97
a47a9c00-5702-8d0e-87ea-5ce32bd83b97
aab39d00-5702-8d0e-87ea-5ce32bd83b97
ea269f00-5702-8d0e-87ea-5ce32bd83b97
b0aaa000-5702-8d0e-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)

3a76705b-7d8a-4912-b913-40fc9bfaf3b4
cddf548a-d41f-459f-890b-399562f9d0c1
06655f03-aa05-45b0-8310-d66cee98ed78
cd8168ad-0523-42d4-b941-e35a5608ddb0
29b45c2b-94ad-4bd8-b8c4-c85f342ce17e
ba7e6d77-32f0-454d-aa6d-7204e63d4309
6eaf2662-e820-43a8-bb43-8f9a07bf296a
636affc7-52b1-4bbb-bdcb-49cb6f656943
1d8832c8-3553-4c26-b36d-f5619c5d2a44
4b71d95f-302a-4072-b464-65f3c7b40a55
07b5bdd9-7e69-43c8-b8ad-43b44debeb48
ad7cdf20-7895-4f80-bae5-ed0e8904f876
de494633-19ec-4773-a787-1db7bb52b199
16d5a976-33c2-4ccd-9adb-a846386887d8
28bfb183-c128-4b55-972a-d62b333024da

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: