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)

019bac76-5bd0-7338-ab4c-70304d857c8c
019bac76-5bd0-74d5-90c7-d2d23425ec8f
019bac76-5bd0-7619-8561-24af9db602ed
019bac76-5bd0-773c-a132-9155c5608590
019bac76-5bd0-7857-8c91-2a09608a5467
019bac76-5bd0-7975-86e1-00e9b0f55c57
019bac76-5bd0-7a94-bb52-5a347a9eb23a
019bac76-5bd0-7bb3-9f8a-0dc7ade26618
019bac76-5bd0-7ccd-a5eb-d5f25a43e172
019bac76-5bd0-7de4-9d6b-5f3e61c00cb8
019bac76-5bd0-7f03-a6cd-b0b90e28b03d
019bac76-5bd1-701d-bfdf-a8fb0a3747a7
019bac76-5bd1-7138-b49f-487939d161ac
019bac76-5bd1-7257-a9b3-7c650ac0fb02
019bac76-5bd1-7371-b7c3-43f4a501bad3

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)

1f0eed2e-2e3e-609a-ac9e-4cf95d479851
1f0eed2e-2e3e-623e-ac9e-4cf95d479851
1f0eed2e-2e3e-632e-ac9e-4cf95d479851
1f0eed2e-2e3e-63f6-ac9e-4cf95d479851
1f0eed2e-2e3e-64be-ac9e-4cf95d479851
1f0eed2e-2e3e-6586-ac9e-4cf95d479851
1f0eed2e-2e3e-664e-ac9e-4cf95d479851
1f0eed2e-2e3e-670c-ac9e-4cf95d479851
1f0eed2e-2e3e-67ca-ac9e-4cf95d479851
1f0eed2e-2e3e-6888-ac9e-4cf95d479851
1f0eed2e-2e3e-69d2-ac9e-4cf95d479851
1f0eed2e-2e3e-6a9a-ac9e-4cf95d479851
1f0eed2e-2e3e-6b6c-ac9e-4cf95d479851
1f0eed2e-2e3e-6c2a-ac9e-4cf95d479851
1f0eed2e-2e3e-6cf2-ac9e-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)

bc15faf3-9436-48fd-a08e-247519c28839
0d3f2ab1-0352-47f3-968a-5ca8e58ac15f
11c0bae4-1fbf-40f5-85ba-c22510edf642
0a88eb18-1397-4943-ad1b-a3661574d214
f5dcda19-73be-4aba-a63d-b353072c7fae
03301420-bf45-41b3-a17f-0d5cd67f3c41
92c72d29-488e-4fb4-a216-2d31cc5cecef
3572d574-c10b-487d-a78c-9315c42994e1
9ae5314f-50f7-48be-9ba7-4461442af463
43308f24-66c4-4d5c-9f0e-90751cb4a3b4
eeea7cec-933e-430d-baba-00c4db35be1f
d1265d1e-6184-43a7-9d1b-693f4d88dab4
af652643-a4a8-4ed4-a117-4a0312b1e868
575cfab3-765e-40a2-91ef-169b2286f323
bebe9f12-6c7b-4251-a94b-7e3523cb8c3e

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)

e2e3f21a-eed2-11f0-ac9e-4cf95d479851
e2e3f27e-eed2-11f0-ac9e-4cf95d479851
e2e3f2e2-eed2-11f0-ac9e-4cf95d479851
e2e3f346-eed2-11f0-ac9e-4cf95d479851
e2e3f3a0-eed2-11f0-ac9e-4cf95d479851
e2e3f404-eed2-11f0-ac9e-4cf95d479851
e2e3f45e-eed2-11f0-ac9e-4cf95d479851
e2e3f4b8-eed2-11f0-ac9e-4cf95d479851
e2e3f512-eed2-11f0-ac9e-4cf95d479851
e2e3f576-eed2-11f0-ac9e-4cf95d479851
e2e3f5e4-eed2-11f0-ac9e-4cf95d479851
e2e3f652-eed2-11f0-ac9e-4cf95d479851
e2e3f6b6-eed2-11f0-ac9e-4cf95d479851
e2e3f71a-eed2-11f0-ac9e-4cf95d479851
e2e3f77e-eed2-11f0-ac9e-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)

8b458f38-4e02-8b00-87ea-5ce32bd83b97
53689038-4e02-8b00-87ea-5ce32bd83b97
8d0b9138-4e02-8b00-87ea-5ce32bd83b97
2c969338-4e02-8b00-87ea-5ce32bd83b97
89289438-4e02-8b00-87ea-5ce32bd83b97
77459538-4e02-8b00-87ea-5ce32bd83b97
21a39638-4e02-8b00-87ea-5ce32bd83b97
def09738-4e02-8b00-87ea-5ce32bd83b97
85499838-4e02-8b00-87ea-5ce32bd83b97
9a7d9938-4e02-8b00-87ea-5ce32bd83b97
ee749a38-4e02-8b00-87ea-5ce32bd83b97
31479b38-4e02-8b00-87ea-5ce32bd83b97
6de49c38-4e02-8b00-87ea-5ce32bd83b97
5edc9d38-4e02-8b00-87ea-5ce32bd83b97
0ab39e38-4e02-8b00-87ea-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: