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)

019de4bd-5103-750b-bb40-544752a208aa
019de4bd-5103-76ad-b6e2-2ddb4e4690c8
019de4bd-5103-7800-b97e-e959795fb7f9
019de4bd-5103-7930-b064-e38dd39594d4
019de4bd-5103-7a52-a0fc-e55be84787ff
019de4bd-5103-7b6d-9377-3e13c89f172f
019de4bd-5103-7c84-b177-d6b1b4216c4f
019de4bd-5103-7da2-a0e0-f1cfdf81eb07
019de4bd-5103-7ebd-a0ed-657a4c0e222c
019de4bd-5103-7fd8-8b3f-a6ec19c15053
019de4bd-5104-70f6-a738-bfc9eb9066e8
019de4bd-5104-7211-adba-cf617f905583
019de4bd-5104-732c-a250-e4bf42b1d068
019de4bd-5104-7446-8c6e-2e78df1e8f52
019de4bd-5104-7561-a24d-74355792e601

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)

1f145893-6adf-6e6a-819e-4cf95d479851
1f145893-6ae0-6068-819e-4cf95d479851
1f145893-6ae0-6162-819e-4cf95d479851
1f145893-6ae0-6248-819e-4cf95d479851
1f145893-6ae0-6324-819e-4cf95d479851
1f145893-6ae0-6400-819e-4cf95d479851
1f145893-6ae0-64d2-819e-4cf95d479851
1f145893-6ae0-65a4-819e-4cf95d479851
1f145893-6ae0-6676-819e-4cf95d479851
1f145893-6ae0-6748-819e-4cf95d479851
1f145893-6ae0-68b0-819e-4cf95d479851
1f145893-6ae0-698c-819e-4cf95d479851
1f145893-6ae0-6a5e-819e-4cf95d479851
1f145893-6ae0-6b3a-819e-4cf95d479851
1f145893-6ae0-6c0c-819e-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)

b2c26eab-5192-48d6-a590-8ca404f75ce2
707d08ec-dcfc-4a46-b9d1-3d73e501383f
0e24f2ee-d30a-4f08-a97e-e02b6579ca7c
316e10ce-9cb4-4851-95d0-cd6313257a4b
534b00df-e820-4c57-b95a-23f9f0c51b41
c2970a80-f99a-482b-9b41-87dfe66d63f4
3fc29442-de82-43d5-aeb0-57e452e93ab3
fc162f29-3d4e-405c-b852-990b6e0fb187
a3a9639a-68ee-480b-920d-057d58f73daf
61543dce-4d0a-4a83-bec1-4fd343faedb5
84787e05-1ff3-4737-8769-2073c736dd20
0e674663-60d2-470f-ab59-dc080bfb3644
4e2c653a-9506-476c-a101-e3d24df26ebf
8d3f2d1f-96a7-4327-b9f6-037bde4fbc0f
80b346dd-6442-485c-b92d-8b503f82d66f

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)

36ae1166-4589-11f1-819e-4cf95d479851
36ae11d4-4589-11f1-819e-4cf95d479851
36ae1238-4589-11f1-819e-4cf95d479851
36ae1292-4589-11f1-819e-4cf95d479851
36ae12f6-4589-11f1-819e-4cf95d479851
36ae13fa-4589-11f1-819e-4cf95d479851
36ae1472-4589-11f1-819e-4cf95d479851
36ae14e0-4589-11f1-819e-4cf95d479851
36ae1544-4589-11f1-819e-4cf95d479851
36ae159e-4589-11f1-819e-4cf95d479851
36ae1602-4589-11f1-819e-4cf95d479851
36ae1666-4589-11f1-819e-4cf95d479851
36ae16b6-4589-11f1-819e-4cf95d479851
36ae1724-4589-11f1-819e-4cf95d479851
36ae1788-4589-11f1-819e-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)

f2e78a2d-4404-8907-87ea-5ce32bd83b97
800b8b2d-4404-8907-87ea-5ce32bd83b97
d1e88c2d-4404-8907-87ea-5ce32bd83b97
3bb08d2d-4404-8907-87ea-5ce32bd83b97
5eca8e2d-4404-8907-87ea-5ce32bd83b97
5e1a8f2d-4404-8907-87ea-5ce32bd83b97
c96c902d-4404-8907-87ea-5ce32bd83b97
0444912d-4404-8907-87ea-5ce32bd83b97
318d932d-4404-8907-87ea-5ce32bd83b97
c4f2942d-4404-8907-87ea-5ce32bd83b97
cb0f952d-4404-8907-87ea-5ce32bd83b97
68c2962d-4404-8907-87ea-5ce32bd83b97
99a9972d-4404-8907-87ea-5ce32bd83b97
66bc982d-4404-8907-87ea-5ce32bd83b97
506e992d-4404-8907-87ea-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: