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)

0199a79f-7d37-7077-8da3-5292402b35b5
0199a79f-7d38-7236-8f4d-62b4e09be4b2
0199a79f-7d38-7382-a9b4-b68d3225a4db
0199a79f-7d38-74ad-af24-9ca1cd6dcc90
0199a79f-7d38-75c7-a23c-f75d44999ae1
0199a79f-7d38-76e6-9d0c-aa73a9e2bb39
0199a79f-7d38-7805-862c-67376fee44b1
0199a79f-7d38-791f-bac4-b32f54ed6628
0199a79f-7d38-7a3e-ae1d-ce09b0b8ac1b
0199a79f-7d38-7b71-a39a-19841e0dcad1
0199a79f-7d38-7cb1-907e-65a44896b1f3
0199a79f-7d38-7dd3-8838-634cae857714
0199a79f-7d38-7fa2-96c9-425051bc7097
0199a79f-7d39-712c-ad0d-92187cd27b0d
0199a79f-7d39-727f-9716-9627059f45b6

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)

1f09ff5d-98cd-63b6-b23d-4cf95d479851
1f09ff5d-98cd-6672-b23d-4cf95d479851
1f09ff5d-98cd-680c-b23d-4cf95d479851
1f09ff5d-98cd-697e-b23d-4cf95d479851
1f09ff5d-98cd-6adc-b23d-4cf95d479851
1f09ff5d-98cd-6c30-b23d-4cf95d479851
1f09ff5d-98cd-6d7a-b23d-4cf95d479851
1f09ff5d-98cd-6ec4-b23d-4cf95d479851
1f09ff5d-98ce-6022-b23d-4cf95d479851
1f09ff5d-98ce-6180-b23d-4cf95d479851
1f09ff5d-98ce-6388-b23d-4cf95d479851
1f09ff5d-98ce-64e6-b23d-4cf95d479851
1f09ff5d-98ce-664e-b23d-4cf95d479851
1f09ff5d-98ce-67b6-b23d-4cf95d479851
1f09ff5d-98ce-6914-b23d-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)

fc57c830-76ac-49e2-8cb2-e8fa410ade11
36d29695-9028-46d8-a5d7-6363887654ae
ebf3d8d6-1257-46c0-9141-b99aa6fe3c68
0ce5f61c-8c63-4863-9f9b-c4703e1b4edc
739d44a9-1773-485e-9fda-b9cfe2e7eadf
17f62433-06aa-4f5f-8da7-74c7a54c5f2d
c94968ad-4762-4529-a101-c34eb03905f5
70fe4a44-fd2f-49d5-89ec-b9417accaec4
7153dfbc-7255-4b78-b912-4cacbf921459
4f19427a-1cf5-4c34-9071-3674fc77f752
e9d786cd-6169-4818-bbd0-b58ed76f10f6
b899483a-c6cc-4c5c-82ff-87fc30fdd56d
b9667977-51ab-4c02-bf55-8241ba22d00f
f4b7df49-fa06-48d7-b40e-2df0b583ffd6
dc89385f-a947-4ad1-9fa3-04a5f3284e07

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)

d98cf030-9ff5-11f0-b23d-4cf95d479851
d98cf0d0-9ff5-11f0-b23d-4cf95d479851
d98cf170-9ff5-11f0-b23d-4cf95d479851
d98cf206-9ff5-11f0-b23d-4cf95d479851
d98cf288-9ff5-11f0-b23d-4cf95d479851
d98cf314-9ff5-11f0-b23d-4cf95d479851
d98cf3b4-9ff5-11f0-b23d-4cf95d479851
d98cf44a-9ff5-11f0-b23d-4cf95d479851
d98cf4e0-9ff5-11f0-b23d-4cf95d479851
d98cf56c-9ff5-11f0-b23d-4cf95d479851
d98cf602-9ff5-11f0-b23d-4cf95d479851
d98cf68e-9ff5-11f0-b23d-4cf95d479851
d98cf71a-9ff5-11f0-b23d-4cf95d479851
d98cf7b0-9ff5-11f0-b23d-4cf95d479851
d98cf846-9ff5-11f0-b23d-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)

5e6a6b0b-4800-8411-87e9-5ce32bd83b97
e5046c0b-4800-8411-87e9-5ce32bd83b97
2cc86d0b-4800-8411-87e9-5ce32bd83b97
f4166e0b-4800-8411-87e9-5ce32bd83b97
541a6f0b-4800-8411-87e9-5ce32bd83b97
fe36700b-4800-8411-87e9-5ce32bd83b97
cf8e710b-4800-8411-87e9-5ce32bd83b97
1d60720b-4800-8411-87e9-5ce32bd83b97
187b730b-4800-8411-87e9-5ce32bd83b97
aea0740b-4800-8411-87e9-5ce32bd83b97
982d750b-4800-8411-87e9-5ce32bd83b97
a937760b-4800-8411-87e9-5ce32bd83b97
6881770b-4800-8411-87e9-5ce32bd83b97
1742780b-4800-8411-87e9-5ce32bd83b97
fd957a0b-4800-8411-87e9-5ce32bd83b97

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: