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)

019cc653-e2f6-7c77-9ad9-f9e7c8713381
019cc653-e2f6-7e5b-8827-06f3862b52ce
019cc653-e2f6-7fbb-9673-a5a0761eabb5
019cc653-e2f7-70e2-be66-4cb60032a2c2
019cc653-e2f7-71fc-9ada-efdf87b1e7b0
019cc653-e2f7-7317-a224-8e0de54ce6e0
019cc653-e2f7-742e-b4ef-db8881c26a2e
019cc653-e2f7-7548-954e-8ca53fd4f882
019cc653-e2f7-7667-b566-386216b3baa6
019cc653-e2f7-7782-9837-65dc043db716
019cc653-e2f7-7898-9c18-8a9f1e6c2c88
019cc653-e2f7-79af-9c64-e98463052b3e
019cc653-e2f7-7ac9-a402-7f09a9f3f890
019cc653-e2f7-7be0-a016-e08eaf8b2d3d
019cc653-e2f7-7cfa-ad9a-5e09dffb0af0

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)

1f119d54-0533-63e8-a2f0-4cf95d479851
1f119d54-0533-6578-a2f0-4cf95d479851
1f119d54-0533-665e-a2f0-4cf95d479851
1f119d54-0533-6726-a2f0-4cf95d479851
1f119d54-0533-67ee-a2f0-4cf95d479851
1f119d54-0533-68ac-a2f0-4cf95d479851
1f119d54-0533-696a-a2f0-4cf95d479851
1f119d54-0533-6a28-a2f0-4cf95d479851
1f119d54-0533-6ae6-a2f0-4cf95d479851
1f119d54-0533-6ba4-a2f0-4cf95d479851
1f119d54-0533-6cf8-a2f0-4cf95d479851
1f119d54-0533-6e10-a2f0-4cf95d479851
1f119d54-0533-6f32-a2f0-4cf95d479851
1f119d54-0533-6ffa-a2f0-4cf95d479851
1f119d54-0534-60b8-a2f0-4cf95d479851

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)

c542db0d-2aa2-4368-bbc8-06c8feeb7f4d
3d280052-d721-4c86-b027-859b36f1a07d
fc97f376-b3f4-46cf-8f42-f5e32202c507
39505280-397d-4814-9904-8448c07f51b6
d6660ac7-355d-4e39-a85c-a246d4289e7f
91d891ee-7131-49fc-ac31-ec737d6725ba
3e9a8bf0-c43c-4ffc-9c95-5d56320cc611
c241122e-87cf-4383-b64a-048cb08e9aaf
f039249c-921f-4a26-bcd8-5137a9d1d155
9f330812-0b73-4b90-bff4-4e7b3cdca19d
9144dbe5-ee9b-49a3-a0c4-e89eea379b44
28c2c38e-0d0b-4b07-8b04-3277238e0c36
5aabba91-b5c6-4a09-b8e9-186b34810f2d
2188407a-fa3a-4567-8e0a-c977325904ed
7f45f976-888b-4a9c-b216-e1bba4b2ad28

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)

405345e0-19d5-11f1-a2f0-4cf95d479851
40534644-19d5-11f1-a2f0-4cf95d479851
405346b2-19d5-11f1-a2f0-4cf95d479851
4053470c-19d5-11f1-a2f0-4cf95d479851
40534770-19d5-11f1-a2f0-4cf95d479851
405347d4-19d5-11f1-a2f0-4cf95d479851
40534838-19d5-11f1-a2f0-4cf95d479851
40534892-19d5-11f1-a2f0-4cf95d479851
405348f6-19d5-11f1-a2f0-4cf95d479851
4053495a-19d5-11f1-a2f0-4cf95d479851
405349c8-19d5-11f1-a2f0-4cf95d479851
40534a2c-19d5-11f1-a2f0-4cf95d479851
40534a90-19d5-11f1-a2f0-4cf95d479851
40534afe-19d5-11f1-a2f0-4cf95d479851
40534b62-19d5-11f1-a2f0-4cf95d479851

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)

bfad500c-ce00-8204-87ea-5ce32bd83b97
4f6f510c-ce00-8204-87ea-5ce32bd83b97
9349520c-ce00-8204-87ea-5ce32bd83b97
58a9530c-ce00-8204-87ea-5ce32bd83b97
143d540c-ce00-8204-87ea-5ce32bd83b97
f31b550c-ce00-8204-87ea-5ce32bd83b97
c6e0560c-ce00-8204-87ea-5ce32bd83b97
73d2570c-ce00-8204-87ea-5ce32bd83b97
1162580c-ce00-8204-87ea-5ce32bd83b97
72dc590c-ce00-8204-87ea-5ce32bd83b97
e20e5a0c-ce00-8204-87ea-5ce32bd83b97
7fef5b0c-ce00-8204-87ea-5ce32bd83b97
e84f5c0c-ce00-8204-87ea-5ce32bd83b97
a46e5d0c-ce00-8204-87ea-5ce32bd83b97
9edd5e0c-ce00-8204-87ea-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: