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)

019cb20d-8e57-73c3-8212-bd42b79acf7d
019cb20d-8e57-77b3-b5f9-2fadf8e40fe9
019cb20d-8e57-7903-8e78-58e374b83494
019cb20d-8e57-7a25-8321-55504e39a6c9
019cb20d-8e57-7b40-99b5-a91f7ead45fb
019cb20d-8e57-7c5b-8b5e-8298890f9537
019cb20d-8e57-7d75-8ff7-c6907b896ffe
019cb20d-8e57-7e90-8216-f1370c3aab03
019cb20d-8e57-7faa-9f7c-ba6526fc4a12
019cb20d-8e58-70c5-9047-d2b3c05acd1c
019cb20d-8e58-71e0-b9cc-a3b7e0904e69
019cb20d-8e58-72f6-8c21-5c14efdf48bd
019cb20d-8e58-740d-9065-eefca9cab2ec
019cb20d-8e58-752c-bc8a-5739e0bb07f7
019cb20d-8e58-7646-9b22-703531c47451

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)

1f116bd4-509a-6202-a6c6-4cf95d479851
1f116bd4-509a-63c4-a6c6-4cf95d479851
1f116bd4-509a-6518-a6c6-4cf95d479851
1f116bd4-509a-65fe-a6c6-4cf95d479851
1f116bd4-509a-66c6-a6c6-4cf95d479851
1f116bd4-509a-678e-a6c6-4cf95d479851
1f116bd4-509a-684c-a6c6-4cf95d479851
1f116bd4-509a-6914-a6c6-4cf95d479851
1f116bd4-509a-69d2-a6c6-4cf95d479851
1f116bd4-509a-6a90-a6c6-4cf95d479851
1f116bd4-509a-6c16-a6c6-4cf95d479851
1f116bd4-509a-6da6-a6c6-4cf95d479851
1f116bd4-509a-6ea0-a6c6-4cf95d479851
1f116bd4-509a-6f72-a6c6-4cf95d479851
1f116bd4-509b-6044-a6c6-4cf95d479851

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)

29f38d17-b820-4d45-bd3c-f7d66f7fb2f2
135ea252-5706-4939-bfc3-16a2317033f8
b9db488e-60fd-4645-9047-3b2877e15b93
650ba6f6-d75f-43fe-a370-f01488ea1ac5
7de0d8d4-e0b8-449a-b496-a31ee51fd02d
df96ecf0-9a61-432e-a9f6-849e171d60b5
3968e648-a90d-4c0c-8949-0b5391b9ae8b
0494adfe-abf0-4a72-a33b-943919524875
c738d60a-3a33-4ea0-a20e-c37f98e0aa6b
396e1ca4-dbfe-4f04-b05e-8731f8204bb2
c0c7dedb-0d60-4dc6-a5a4-9684c13373a9
82abfe6c-be8a-428f-a14d-9dcbae26d8d9
e4b66e5c-1eef-4e4f-811b-1542eb4194b0
bfae3a7c-32d3-4083-b74a-ad67e5a126ef
9a443d61-b6c4-4f86-83e8-2de4f90b9a7a

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)

4509b56c-16bd-11f1-a6c6-4cf95d479851
4509b5da-16bd-11f1-a6c6-4cf95d479851
4509b65c-16bd-11f1-a6c6-4cf95d479851
4509b6e8-16bd-11f1-a6c6-4cf95d479851
4509b756-16bd-11f1-a6c6-4cf95d479851
4509b7ba-16bd-11f1-a6c6-4cf95d479851
4509b81e-16bd-11f1-a6c6-4cf95d479851
4509b882-16bd-11f1-a6c6-4cf95d479851
4509b8e6-16bd-11f1-a6c6-4cf95d479851
4509b94a-16bd-11f1-a6c6-4cf95d479851
4509b9ae-16bd-11f1-a6c6-4cf95d479851
4509ba12-16bd-11f1-a6c6-4cf95d479851
4509ba6c-16bd-11f1-a6c6-4cf95d479851
4509bad0-16bd-11f1-a6c6-4cf95d479851
4509bb3e-16bd-11f1-a6c6-4cf95d479851

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)

6e94cf3a-2801-8e03-87ea-5ce32bd83b97
7ea4d03a-2801-8e03-87ea-5ce32bd83b97
cec3d13a-2801-8e03-87ea-5ce32bd83b97
3064d23a-2801-8e03-87ea-5ce32bd83b97
6c53d33a-2801-8e03-87ea-5ce32bd83b97
0942d43a-2801-8e03-87ea-5ce32bd83b97
7b36d53a-2801-8e03-87ea-5ce32bd83b97
db40d63a-2801-8e03-87ea-5ce32bd83b97
120cd73a-2801-8e03-87ea-5ce32bd83b97
865cd83a-2801-8e03-87ea-5ce32bd83b97
7401d93a-2801-8e03-87ea-5ce32bd83b97
b584da3a-2801-8e03-87ea-5ce32bd83b97
844edb3a-2801-8e03-87ea-5ce32bd83b97
5637dc3a-2801-8e03-87ea-5ce32bd83b97
5bd3dd3a-2801-8e03-87ea-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: