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)

01a01813-45ec-7ede-99f3-b83f9965191f
01a01813-45ed-7103-998b-0ceaeb27f3eb
01a01813-45ed-7257-862e-81abc8f530b0
01a01813-45ed-7379-92ff-970ce59b7a62
01a01813-45ed-7498-bad0-f3da07186e6e
01a01813-45ed-75b3-a859-b2cf89646539
01a01813-45ed-76d1-b61d-cb3193e27cd5
01a01813-45ed-77f0-852b-b56f157cf160
01a01813-45ed-790b-9fe5-019204ac79ac
01a01813-45ed-7a25-899d-5b436f8d0bc5
01a01813-45ed-7b4c-b0e7-897b7d5e0384
01a01813-45ed-7c6b-bd2e-ceba8b6d9a80
01a01813-45ed-7d86-81cf-dd8dad6e2676
01a01813-45ed-7ea4-be2d-5df3d64c626c
01a01813-45ed-7fbf-86cd-27a28dce34e7

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)

1f19b7e8-45ce-64c8-9f06-4cf95d479851
1f19b7e8-45ce-66d0-9f06-4cf95d479851
1f19b7e8-45ce-67c0-9f06-4cf95d479851
1f19b7e8-45ce-6888-9f06-4cf95d479851
1f19b7e8-45ce-6950-9f06-4cf95d479851
1f19b7e8-45ce-6a18-9f06-4cf95d479851
1f19b7e8-45ce-6ae0-9f06-4cf95d479851
1f19b7e8-45ce-6ba8-9f06-4cf95d479851
1f19b7e8-45ce-6c70-9f06-4cf95d479851
1f19b7e8-45ce-6d2e-9f06-4cf95d479851
1f19b7e8-45ce-6e96-9f06-4cf95d479851
1f19b7e8-45ce-6f72-9f06-4cf95d479851
1f19b7e8-45cf-6030-9f06-4cf95d479851
1f19b7e8-45cf-6102-9f06-4cf95d479851
1f19b7e8-45cf-61ca-9f06-4cf95d479851

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)

845cf29c-9b7e-11f1-9f06-4cf95d479851
845cf300-9b7e-11f1-9f06-4cf95d479851
845cf364-9b7e-11f1-9f06-4cf95d479851
845cf436-9b7e-11f1-9f06-4cf95d479851
845cf4ae-9b7e-11f1-9f06-4cf95d479851
845cf512-9b7e-11f1-9f06-4cf95d479851
845cf56c-9b7e-11f1-9f06-4cf95d479851
845cf5d0-9b7e-11f1-9f06-4cf95d479851
845cf62a-9b7e-11f1-9f06-4cf95d479851
845cf698-9b7e-11f1-9f06-4cf95d479851
845cf6fc-9b7e-11f1-9f06-4cf95d479851
845cf760-9b7e-11f1-9f06-4cf95d479851
845cf7ce-9b7e-11f1-9f06-4cf95d479851
845cf832-9b7e-11f1-9f06-4cf95d479851
845cf896-9b7e-11f1-9f06-4cf95d479851

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)

95c56833-d400-870e-87ea-5ce32bd83b97
3a236933-d400-870e-87ea-5ce32bd83b97
32866a33-d400-870e-87ea-5ce32bd83b97
fb0f6b33-d400-870e-87ea-5ce32bd83b97
a3ae6c33-d400-870e-87ea-5ce32bd83b97
99ac6d33-d400-870e-87ea-5ce32bd83b97
c3236e33-d400-870e-87ea-5ce32bd83b97
80d76f33-d400-870e-87ea-5ce32bd83b97
24167033-d400-870e-87ea-5ce32bd83b97
688e7133-d400-870e-87ea-5ce32bd83b97
39357233-d400-870e-87ea-5ce32bd83b97
bb3e7333-d400-870e-87ea-5ce32bd83b97
64e47433-d400-870e-87ea-5ce32bd83b97
f5f97533-d400-870e-87ea-5ce32bd83b97
62527633-d400-870e-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)

3e119ce0-100a-4417-94b6-3392f0e796e7
54d3c52b-d029-4d62-9533-2e7078161dd3
7945e5ee-6b8b-4f32-b86c-e9c37d118271
0635b5c3-d1f7-458f-a55d-51af2eee2bf6
e1d1c120-ffee-487b-b66b-ec1b84c0d8b5
27970b5a-bb99-40f2-8dbc-a51ff49e70a6
82caec31-a2f7-4a55-89a4-447aefdfc43a
bb4af456-c713-4d90-a507-d9568eaef47b
438c6862-05d9-4dbf-b413-3736e57f9f48
612bacee-3333-40b2-9c4a-1362c89afabd
b25ad02e-1fc4-466a-8e82-7b9405a6f948
2ced19d4-fed8-40ad-837e-1b87e2823e0e
0b31b303-63dd-4a25-ba2a-89f29d470d31
b9bf959f-0435-4e37-a1e8-8c2c893ad9a5
5e87ffec-ac87-4071-a2d0-5e4b40dcb0b1

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: