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)

019bbe97-8399-7a0d-92ba-f5f673ee5c2f
019bbe97-8399-7ba6-963b-5e93bb4bd8cc
019bbe97-8399-7ce2-83c3-d480a2ae8748
019bbe97-8399-7e05-afe5-f748a2ca69e6
019bbe97-8399-7f27-aff9-98a42a099148
019bbe97-839a-703e-a7a2-de5f6aa16562
019bbe97-839a-7159-bc29-610ae62c86f5
019bbe97-839a-726f-8ae8-53f5baba405a
019bbe97-839a-738a-a8f7-5ca391505a51
019bbe97-839a-74a4-ac15-2af572b33ac5
019bbe97-839a-75bf-8885-6b280448696d
019bbe97-839a-76da-8084-996df33c75a1
019bbe97-839a-77f0-8594-18c334ee6a00
019bbe97-839a-7907-bb6f-ae7b7efaab76
019bbe97-839a-7a1d-96c7-68d29a2211c4

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)

1f0f1971-2060-6c4c-aace-4cf95d479851
1f0f1971-2060-6df0-aace-4cf95d479851
1f0f1971-2060-6ee0-aace-4cf95d479851
1f0f1971-2060-6fb2-aace-4cf95d479851
1f0f1971-2061-6084-aace-4cf95d479851
1f0f1971-2061-614c-aace-4cf95d479851
1f0f1971-2061-6214-aace-4cf95d479851
1f0f1971-2061-62e6-aace-4cf95d479851
1f0f1971-2061-63ae-aace-4cf95d479851
1f0f1971-2061-6476-aace-4cf95d479851
1f0f1971-2061-65de-aace-4cf95d479851
1f0f1971-2061-66b0-aace-4cf95d479851
1f0f1971-2061-6778-aace-4cf95d479851
1f0f1971-2061-684a-aace-4cf95d479851
1f0f1971-2061-6944-aace-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)

a864ea77-a33b-421f-af18-6dec57c39a77
ab323322-0f8f-425b-a722-dac1ae5c82a5
7a2c2b29-d1d8-4ba6-a9f0-af93d7830b35
25dbe1f6-dd03-41fd-ad1d-bd5ddff4cfa2
fe15fab1-1995-4f5d-b316-f4aef37d29c8
c90e4b11-3991-4887-a73a-a12c9c4b489b
231b841b-7f19-433e-a90a-f55406b7b109
94f4d98d-399d-4c7f-8b83-73cd18f1d0cb
6c937215-b6ed-47fe-b2d0-8c626c439422
736cfcf8-d037-43d3-bbbd-1596f5713061
94583de1-1d37-43eb-8d00-6fa0d1bcde25
9523d518-43e9-4bf6-8006-4c1e26d5bb9d
7fb51ac2-d04d-48c0-80fa-cdf6952040e3
9675a916-cc96-49cb-b42b-0ba6f98915ae
96c3392a-50fb-4bf0-b316-241cbd39ef76

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)

12061e9e-f197-11f0-aace-4cf95d479851
12061f02-f197-11f0-aace-4cf95d479851
12061f66-f197-11f0-aace-4cf95d479851
12061fc0-f197-11f0-aace-4cf95d479851
1206202e-f197-11f0-aace-4cf95d479851
12062092-f197-11f0-aace-4cf95d479851
120620ec-f197-11f0-aace-4cf95d479851
12062150-f197-11f0-aace-4cf95d479851
120621aa-f197-11f0-aace-4cf95d479851
12062218-f197-11f0-aace-4cf95d479851
12062286-f197-11f0-aace-4cf95d479851
120622e0-f197-11f0-aace-4cf95d479851
12062344-f197-11f0-aace-4cf95d479851
1206239e-f197-11f0-aace-4cf95d479851
120623f8-f197-11f0-aace-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)

b7965213-3c05-8e00-87ea-5ce32bd83b97
d6ae5313-3c05-8e00-87ea-5ce32bd83b97
4cad5413-3c05-8e00-87ea-5ce32bd83b97
69f45613-3c05-8e00-87ea-5ce32bd83b97
d3725713-3c05-8e00-87ea-5ce32bd83b97
0ff35813-3c05-8e00-87ea-5ce32bd83b97
8df35913-3c05-8e00-87ea-5ce32bd83b97
70875a13-3c05-8e00-87ea-5ce32bd83b97
eef25b13-3c05-8e00-87ea-5ce32bd83b97
474f5c13-3c05-8e00-87ea-5ce32bd83b97
d68d5d13-3c05-8e00-87ea-5ce32bd83b97
d14a5e13-3c05-8e00-87ea-5ce32bd83b97
6e095f13-3c05-8e00-87ea-5ce32bd83b97
5dfe6013-3c05-8e00-87ea-5ce32bd83b97
b80e6113-3c05-8e00-87ea-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: