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)

019c73fb-7bfa-7d61-b11c-63651d25380e
019c73fb-7bfa-7f4c-b16b-17445119b8ee
019c73fb-7bfb-7094-a168-2ff737714895
019c73fb-7bfb-71b7-8dd5-f92e87772a96
019c73fb-7bfb-72d1-9ef8-7d01f8ab9abd
019c73fb-7bfb-73f0-a5b2-594619681634
019c73fb-7bfb-750b-8b00-89a2ce53c8f9
019c73fb-7bfb-7629-819a-572bd9e14d26
019c73fb-7bfb-7748-864b-f8f51fdcf1df
019c73fb-7bfb-7863-9502-83d414111c0c
019c73fb-7bfb-797d-bc60-d58556b259ef
019c73fb-7bfb-7a9c-b749-a42f3d88f346
019c73fb-7bfb-7bb7-9b22-d999895a9190
019c73fb-7bfb-7cd1-b9c8-86b5c7247df9
019c73fb-7bfb-7dec-9b5c-d82cd1a195cd

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)

1f10d44a-31c6-6410-9ae6-4cf95d479851
1f10d44a-31c6-65aa-9ae6-4cf95d479851
1f10d44a-31c6-6690-9ae6-4cf95d479851
1f10d44a-31c6-6758-9ae6-4cf95d479851
1f10d44a-31c6-6820-9ae6-4cf95d479851
1f10d44a-31c6-68e8-9ae6-4cf95d479851
1f10d44a-31c6-69a6-9ae6-4cf95d479851
1f10d44a-31c6-6b04-9ae6-4cf95d479851
1f10d44a-31c6-6bf4-9ae6-4cf95d479851
1f10d44a-31c6-6cb2-9ae6-4cf95d479851
1f10d44a-31c6-6df2-9ae6-4cf95d479851
1f10d44a-31c6-6ece-9ae6-4cf95d479851
1f10d44a-31c6-6f96-9ae6-4cf95d479851
1f10d44a-31c7-605e-9ae6-4cf95d479851
1f10d44a-31c7-611c-9ae6-4cf95d479851

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)

e8e1e22c-b738-409e-ad12-2dd38823b326
771ed5cf-eca6-4a46-9438-cf0baeeb02d4
37cae0ba-364a-4d7b-9b1a-8c2024fc6982
01b97165-7e26-4531-aa1a-83b13c5d32ec
fefb4c5d-d37f-4a3e-9c0b-5dd65e422ada
de71ff95-1a2a-405b-be90-883ddffd333a
9cbd94db-d322-4d04-9d78-91a567a16d3d
35ffd0f8-990c-4cd5-a176-0724fafbe561
a580d5f9-ca2b-42b1-85c8-4937305da53b
604671ce-07b5-4e04-afa4-174e11a7737a
41dc662a-748f-44c5-bd7a-1b47151b1ea0
df8a3a85-8b7a-472c-85d5-ab70e680474a
14b86b1f-3873-40d1-a155-191ae10cfab6
0c35a75a-cd78-4641-8dc0-37f52b7b1881
0b630854-595a-4799-b7b3-e09139273641

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)

a31c763a-0d44-11f1-9ae6-4cf95d479851
a31c769e-0d44-11f1-9ae6-4cf95d479851
a31c7702-0d44-11f1-9ae6-4cf95d479851
a31c7766-0d44-11f1-9ae6-4cf95d479851
a31c77ca-0d44-11f1-9ae6-4cf95d479851
a31c7824-0d44-11f1-9ae6-4cf95d479851
a31c7888-0d44-11f1-9ae6-4cf95d479851
a31c78ec-0d44-11f1-9ae6-4cf95d479851
a31c7946-0d44-11f1-9ae6-4cf95d479851
a31c79a0-0d44-11f1-9ae6-4cf95d479851
a31c7a04-0d44-11f1-9ae6-4cf95d479851
a31c7a68-0d44-11f1-9ae6-4cf95d479851
a31c7ac2-0d44-11f1-9ae6-4cf95d479851
a31c7b26-0d44-11f1-9ae6-4cf95d479851
a31c7b8a-0d44-11f1-9ae6-4cf95d479851

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)

65eb112f-dc00-8203-87ea-5ce32bd83b97
60a5122f-dc00-8203-87ea-5ce32bd83b97
5ccc132f-dc00-8203-87ea-5ce32bd83b97
1600152f-dc00-8203-87ea-5ce32bd83b97
cee1162f-dc00-8203-87ea-5ce32bd83b97
cffd172f-dc00-8203-87ea-5ce32bd83b97
3ea2182f-dc00-8203-87ea-5ce32bd83b97
20be192f-dc00-8203-87ea-5ce32bd83b97
063d1a2f-dc00-8203-87ea-5ce32bd83b97
3bf61b2f-dc00-8203-87ea-5ce32bd83b97
536b1c2f-dc00-8203-87ea-5ce32bd83b97
ca2e1d2f-dc00-8203-87ea-5ce32bd83b97
e8231e2f-dc00-8203-87ea-5ce32bd83b97
c85c1f2f-dc00-8203-87ea-5ce32bd83b97
c5e0202f-dc00-8203-87ea-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: