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)

019af918-e31f-77e0-bf43-ce54607baf6e
019af918-e31f-7971-a025-d9eb9c4140c6
019af918-e31f-7ab5-8ec3-b825266cf2ca
019af918-e31f-7bd8-b0af-29b4ab49e1a3
019af918-e31f-7cf2-9c63-000efeabd458
019af918-e31f-7e0d-8296-05a39e2ef119
019af918-e31f-7f27-b462-10367398ce01
019af918-e320-7042-a0a9-d9b64f0b87ac
019af918-e320-7161-925e-6b88d5922129
019af918-e320-727b-bf36-f2c783ae9623
019af918-e320-7396-89e4-ecd96818aede
019af918-e320-74b5-b833-afd2f44c1b41
019af918-e320-75cf-b4c5-7b9444e3f652
019af918-e320-76ea-b511-87f7fd6c6f83
019af918-e320-7805-919c-b1217cde0cf4

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)

1f0d3746-fa96-6966-a0cf-4cf95d479851
1f0d3746-fa96-6b14-a0cf-4cf95d479851
1f0d3746-fa96-6bfa-a0cf-4cf95d479851
1f0d3746-fa96-6cd6-a0cf-4cf95d479851
1f0d3746-fa96-6d9e-a0cf-4cf95d479851
1f0d3746-fa96-6e66-a0cf-4cf95d479851
1f0d3746-fa96-6f2e-a0cf-4cf95d479851
1f0d3746-fa96-6ff6-a0cf-4cf95d479851
1f0d3746-fa97-60be-a0cf-4cf95d479851
1f0d3746-fa97-6186-a0cf-4cf95d479851
1f0d3746-fa97-62c6-a0cf-4cf95d479851
1f0d3746-fa97-6398-a0cf-4cf95d479851
1f0d3746-fa97-6460-a0cf-4cf95d479851
1f0d3746-fa97-6528-a0cf-4cf95d479851
1f0d3746-fa97-65f0-a0cf-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)

a91f1513-08a9-49a2-b9e5-2e5362dba7e6
586b1efe-bed7-4d38-9e9a-cd80ebb922e5
36fc46bb-892c-4527-a543-f88e68a327e7
3c54fee2-0da8-4411-8ee2-ca40a83205f2
fc43e48d-d4ea-4638-a2a9-94755a267364
546e3a4e-9bb6-43cd-bd5c-b7f60783177a
361affb0-bb8a-4df6-9c7b-93afc0342f55
f140d1e2-a303-4385-9bcf-df22ed5cb9b3
215d752f-be3a-459e-a32d-bec1882b2702
b5e5141c-cab1-4454-8130-f85127d9905b
0511c9a6-758f-4efa-84c6-1faf1413187d
9008063f-b3b2-44b4-b740-95823354ebef
01d38a5d-84e4-46f9-8330-25540e295e86
2651e30c-aa98-4abb-99f4-6a46641a8c57
d7a3a0b2-e51e-47c1-908b-04edbec56a4c

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)

6fa97b18-d374-11f0-a0cf-4cf95d479851
6fa97b86-d374-11f0-a0cf-4cf95d479851
6fa97bf4-d374-11f0-a0cf-4cf95d479851
6fa97c58-d374-11f0-a0cf-4cf95d479851
6fa97cc6-d374-11f0-a0cf-4cf95d479851
6fa97d2a-d374-11f0-a0cf-4cf95d479851
6fa97d8e-d374-11f0-a0cf-4cf95d479851
6fa97df2-d374-11f0-a0cf-4cf95d479851
6fa97e56-d374-11f0-a0cf-4cf95d479851
6fa97eba-d374-11f0-a0cf-4cf95d479851
6fa97f1e-d374-11f0-a0cf-4cf95d479851
6fa97f78-d374-11f0-a0cf-4cf95d479851
6fa97fd2-d374-11f0-a0cf-4cf95d479851
6fa98036-d374-11f0-a0cf-4cf95d479851
6fa9809a-d374-11f0-a0cf-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)

7a3a2731-4403-8515-87e9-5ce32bd83b97
78a82831-4403-8515-87e9-5ce32bd83b97
cbf72931-4403-8515-87e9-5ce32bd83b97
b65e2a31-4403-8515-87e9-5ce32bd83b97
c6592b31-4403-8515-87e9-5ce32bd83b97
9a2c2c31-4403-8515-87e9-5ce32bd83b97
77092d31-4403-8515-87e9-5ce32bd83b97
956a2e31-4403-8515-87e9-5ce32bd83b97
db302f31-4403-8515-87e9-5ce32bd83b97
c8a63031-4403-8515-87e9-5ce32bd83b97
750e3131-4403-8515-87e9-5ce32bd83b97
39e43331-4403-8515-87e9-5ce32bd83b97
88eb3431-4403-8515-87e9-5ce32bd83b97
9d1d3531-4403-8515-87e9-5ce32bd83b97
38403631-4403-8515-87e9-5ce32bd83b97

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

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: