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)

0190f2f8-d045-76a0-a11f-b674f7e7d354
0190f2f8-d045-783a-b587-ee47e1884571
0190f2f8-d045-797d-aac7-2c6559380760
0190f2f8-d045-7aa4-be29-e77a0ad3fdbb
0190f2f8-d045-7bbf-a559-eda905bfc129
0190f2f8-d045-7cda-ad94-4e4f3c7c8fd4
0190f2f8-d045-7df8-8c22-87ec5b222c1b
0190f2f8-d045-7f13-ad5e-25cbc79e4156
0190f2f8-d046-702e-9819-c83149403cf4
0190f2f8-d046-714c-9ac1-64a2c1a540cc
0190f2f8-d046-7267-9b37-f952874cfc74
0190f2f8-d046-7382-9acd-a6793ac075b1
0190f2f8-d046-749c-b845-596eb0c05dbf
0190f2f8-d046-75bb-ac8c-28b31f86e2e4
0190f2f8-d046-76d5-8b5f-5ab6e91ae95c

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)

1ef4be52-ac90-6350-b434-4cf95d479851
1ef4be52-ac90-64fe-b434-4cf95d479851
1ef4be52-ac90-65ee-b434-4cf95d479851
1ef4be52-ac90-66c0-b434-4cf95d479851
1ef4be52-ac90-6792-b434-4cf95d479851
1ef4be52-ac90-6864-b434-4cf95d479851
1ef4be52-ac90-692c-b434-4cf95d479851
1ef4be52-ac90-69fe-b434-4cf95d479851
1ef4be52-ac90-6ac6-b434-4cf95d479851
1ef4be52-ac90-6b8e-b434-4cf95d479851
1ef4be52-ac90-6cd8-b434-4cf95d479851
1ef4be52-ac90-6db4-b434-4cf95d479851
1ef4be52-ac90-6e7c-b434-4cf95d479851
1ef4be52-ac90-6f44-b434-4cf95d479851
1ef4be52-ac91-6016-b434-4cf95d479851

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)

654ca6b7-efbb-44ef-881e-e978b4f22cf5
f2d8513d-c0e6-4dab-a4ac-3aefeebdf321
b9505ae6-3b07-49fe-b03f-b274787fded4
88d9abb7-629f-4dfa-9fd5-60341c6301a7
e84d55e9-4e2f-4770-ae04-84af359efd63
877fad30-fcca-46c3-9c47-603f05f17eb1
3a8f6c87-ea37-4b20-9427-688a7a412601
724ce2c3-c444-4119-9709-f8d62fc5c384
8f162048-9124-4c86-919f-ca60e14928d3
88f59106-e4d5-4907-9a34-a239e481b038
3adac547-32b3-41a1-86af-c39a9dc4002c
49e7be27-9673-449a-9e25-aa2d2afdec39
235453f6-97c8-4269-b315-922311932a42
b9911eb2-3e44-438f-88e8-0a9e3878b2e4
2bb0e7f9-7c56-4b43-a637-b51d4cd9d0cb

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)

2ac91548-4be5-11ef-b434-4cf95d479851
2ac915ac-4be5-11ef-b434-4cf95d479851
2ac91610-4be5-11ef-b434-4cf95d479851
2ac91674-4be5-11ef-b434-4cf95d479851
2ac916e2-4be5-11ef-b434-4cf95d479851
2ac9173c-4be5-11ef-b434-4cf95d479851
2ac917aa-4be5-11ef-b434-4cf95d479851
2ac91818-4be5-11ef-b434-4cf95d479851
2ac9187c-4be5-11ef-b434-4cf95d479851
2ac918e0-4be5-11ef-b434-4cf95d479851
2ac91944-4be5-11ef-b434-4cf95d479851
2ac919a8-4be5-11ef-b434-4cf95d479851
2ac91a16-4be5-11ef-b434-4cf95d479851
2ac91a7a-4be5-11ef-b434-4cf95d479851
2ac91ade-4be5-11ef-b434-4cf95d479851

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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

49e7eb0a-01a0-80d1-87e8-5ce32bd83b96
e5a9ec0a-01a0-80d1-87e8-5ce32bd83b96
4ed5ed0a-01a0-80d1-87e8-5ce32bd83b96
eb0eee0a-01a0-80d1-87e8-5ce32bd83b96
8a6cef0a-01a0-80d1-87e8-5ce32bd83b96
4e5bf00a-01a0-80d1-87e8-5ce32bd83b96
d9aaf10a-01a0-80d1-87e8-5ce32bd83b96
00fcf20a-01a0-80d1-87e8-5ce32bd83b96
b00af30a-01a0-80d1-87e8-5ce32bd83b96
b8c1f40a-01a0-80d1-87e8-5ce32bd83b96
8941f50a-01a0-80d1-87e8-5ce32bd83b96
2994f60a-01a0-80d1-87e8-5ce32bd83b96
29b0f70a-01a0-80d1-87e8-5ce32bd83b96
5362f80a-01a0-80d1-87e8-5ce32bd83b96
3e29f90a-01a0-80d1-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: