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)

019bb646-ebb5-72fe-b29d-233b542fbcab
019bb646-ebb5-7494-b0e8-8545f6ba62e3
019bb646-ebb5-75cf-8dc1-80ef93230d77
019bb646-ebb5-76ee-92ec-125f558d4cde
019bb646-ebb5-780d-8033-fc893c28bb25
019bb646-ebb5-7927-a5a5-c28b9d4be749
019bb646-ebb5-7a42-b4ff-84eb4c7e070d
019bb646-ebb5-7b5d-b5e6-ca26e13ade9f
019bb646-ebb5-7c73-8491-98df71d9cd9c
019bb646-ebb5-7d8a-915e-a7f3da1d7016
019bb646-ebb5-7ea4-83b8-db6dd664f8df
019bb646-ebb5-7fbb-866a-95fda10f5d77
019bb646-ebb6-70d5-b46d-b7420067a170
019bb646-ebb6-71f0-a2f2-5cdb2b0321e2
019bb646-ebb6-730b-9292-f1c0f88f0809

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)

1f0f0524-5d8c-608c-9754-4cf95d479851
1f0f0524-5d8c-6226-9754-4cf95d479851
1f0f0524-5d8c-630c-9754-4cf95d479851
1f0f0524-5d8c-63d4-9754-4cf95d479851
1f0f0524-5d8c-6492-9754-4cf95d479851
1f0f0524-5d8c-655a-9754-4cf95d479851
1f0f0524-5d8c-660e-9754-4cf95d479851
1f0f0524-5d8c-66cc-9754-4cf95d479851
1f0f0524-5d8c-678a-9754-4cf95d479851
1f0f0524-5d8c-6852-9754-4cf95d479851
1f0f0524-5d8c-697e-9754-4cf95d479851
1f0f0524-5d8c-6a50-9754-4cf95d479851
1f0f0524-5d8c-6b04-9754-4cf95d479851
1f0f0524-5d8c-6bc2-9754-4cf95d479851
1f0f0524-5d8c-6c80-9754-4cf95d479851

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)

a0627bde-f42e-47ba-8c84-ed7de951ba9c
27768887-ea20-47ba-828a-f9f63f4f518c
b06e6870-378d-4a70-bed6-77a0895c1942
ea07e801-f07b-40e6-8a4e-379e83805b45
b4a155d1-dc6b-4efb-ae85-8e1fe46d98c4
97a21ec8-0fe7-441a-babf-deb54a8a6c73
edcdc10b-0bc5-4b51-b43e-0538eee7928b
951dc5d8-ffd9-464d-b583-3de6b956213d
695f8d9f-8662-4eea-8bc6-481cd3f0f257
16a5b2f7-5ec4-4906-a96e-ae00fb7e4b73
0d6b438d-6fe8-42bf-9b43-3616fb6767e3
41d3910a-dfc2-42d0-9b6f-4830b66df1fb
69c498ee-4add-4367-aafd-ff13f58aceb0
e2e4fa71-43e2-4568-be82-4659b8825738
6ae5e9c1-21c6-48c6-a60d-3b3f9733558b

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)

45d8d194-f052-11f0-9754-4cf95d479851
45d8d1f8-f052-11f0-9754-4cf95d479851
45d8d252-f052-11f0-9754-4cf95d479851
45d8d2b6-f052-11f0-9754-4cf95d479851
45d8d31a-f052-11f0-9754-4cf95d479851
45d8d37e-f052-11f0-9754-4cf95d479851
45d8d3ec-f052-11f0-9754-4cf95d479851
45d8d450-f052-11f0-9754-4cf95d479851
45d8d4aa-f052-11f0-9754-4cf95d479851
45d8d50e-f052-11f0-9754-4cf95d479851
45d8d568-f052-11f0-9754-4cf95d479851
45d8d5cc-f052-11f0-9754-4cf95d479851
45d8d630-f052-11f0-9754-4cf95d479851
45d8d694-f052-11f0-9754-4cf95d479851
45d8d6ee-f052-11f0-9754-4cf95d479851

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)

8550d413-c701-8d00-87ea-5ce32bd83b97
2f18d513-c701-8d00-87ea-5ce32bd83b97
4163d613-c701-8d00-87ea-5ce32bd83b97
de57d713-c701-8d00-87ea-5ce32bd83b97
0425d813-c701-8d00-87ea-5ce32bd83b97
3ae8d913-c701-8d00-87ea-5ce32bd83b97
1b1dda13-c701-8d00-87ea-5ce32bd83b97
5983db13-c701-8d00-87ea-5ce32bd83b97
c509dc13-c701-8d00-87ea-5ce32bd83b97
e4d9dd13-c701-8d00-87ea-5ce32bd83b97
b77bde13-c701-8d00-87ea-5ce32bd83b97
e818df13-c701-8d00-87ea-5ce32bd83b97
25d2e013-c701-8d00-87ea-5ce32bd83b97
b12ce113-c701-8d00-87ea-5ce32bd83b97
d40ee213-c701-8d00-87ea-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: