UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

01a0dcfe-46fc-7acd-b890-8f42d8490d1e
01a0dcfe-46fc-7cea-a890-9eff250e1fed
01a0dcfe-46fc-7e29-bf2c-fc73a404fba6
01a0dcfe-46fc-7f48-8dc9-2a7fe65de210
01a0dcfe-46fd-7063-8986-f1d22c478c45
01a0dcfe-46fd-717d-a436-167ded0ba93c
01a0dcfe-46fd-7294-80dd-776a6b7fa55d
01a0dcfe-46fd-73d8-ac09-158c5f8ef611
01a0dcfe-46fd-750f-954c-56880d07e5e2
01a0dcfe-46fd-7632-889a-fd779b2cb9f3
01a0dcfe-46fd-774c-8a3d-30d363453b49
01a0dcfe-46fd-786f-a046-7a2449179494
01a0dcfe-46fd-7986-be17-3ed0c517e8c1
01a0dcfe-46fd-7aa0-acb6-422645fe2fd9
01a0dcfe-46fd-7bb7-a4d4-d993b3ce10fc

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)

1f1b98aa-0365-6df8-a31f-4cf95d479851
1f1b98aa-0365-6ff6-a31f-4cf95d479851
1f1b98aa-0366-60f0-a31f-4cf95d479851
1f1b98aa-0366-61c2-a31f-4cf95d479851
1f1b98aa-0366-629e-a31f-4cf95d479851
1f1b98aa-0366-6370-a31f-4cf95d479851
1f1b98aa-0366-6442-a31f-4cf95d479851
1f1b98aa-0366-6514-a31f-4cf95d479851
1f1b98aa-0366-65dc-a31f-4cf95d479851
1f1b98aa-0366-66ae-a31f-4cf95d479851
1f1b98aa-0366-6848-a31f-4cf95d479851
1f1b98aa-0366-69c4-a31f-4cf95d479851
1f1b98aa-0366-6b18-a31f-4cf95d479851
1f1b98aa-0366-6c08-a31f-4cf95d479851
1f1b98aa-0366-6cda-a31f-4cf95d479851

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)

a0366dc0-b98a-11f1-a31f-4cf95d479851
a0366e24-b98a-11f1-a31f-4cf95d479851
a0366e88-b98a-11f1-a31f-4cf95d479851
a0366eec-b98a-11f1-a31f-4cf95d479851
a0366f50-b98a-11f1-a31f-4cf95d479851
a0366faa-b98a-11f1-a31f-4cf95d479851
a0367004-b98a-11f1-a31f-4cf95d479851
a0367072-b98a-11f1-a31f-4cf95d479851
a03670d6-b98a-11f1-a31f-4cf95d479851
a036713a-b98a-11f1-a31f-4cf95d479851
a0367194-b98a-11f1-a31f-4cf95d479851
a03671f8-b98a-11f1-a31f-4cf95d479851
a0367266-b98a-11f1-a31f-4cf95d479851
a03672ca-b98a-11f1-a31f-4cf95d479851
a0367324-b98a-11f1-a31f-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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

9d1af906-2b02-8d10-87ea-5ce32bd83b97
7732fa06-2b02-8d10-87ea-5ce32bd83b97
3884fb06-2b02-8d10-87ea-5ce32bd83b97
1dd0fc06-2b02-8d10-87ea-5ce32bd83b97
a981fd06-2b02-8d10-87ea-5ce32bd83b97
81f6fe06-2b02-8d10-87ea-5ce32bd83b97
f26aff06-2b02-8d10-87ea-5ce32bd83b97
92c50107-2b02-8d10-87ea-5ce32bd83b97
30c40207-2b02-8d10-87ea-5ce32bd83b97
a1040307-2b02-8d10-87ea-5ce32bd83b97
94cc0407-2b02-8d10-87ea-5ce32bd83b97
7a000507-2b02-8d10-87ea-5ce32bd83b97
db600607-2b02-8d10-87ea-5ce32bd83b97
5a8e0707-2b02-8d10-87ea-5ce32bd83b97
bb1f0807-2b02-8d10-87ea-5ce32bd83b97

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)

0f68a724-41ff-4374-b161-5d8cf159f1f9
e55d38f4-17de-4bfd-af0f-9835b1c104ce
311ac29a-1a6b-4fe5-a680-2c7761808b0b
4b277712-5bbc-4007-a45a-aae16b7836e3
61446aaa-474e-4f6e-b63c-35ac4db0b29c
6cd0da46-5c59-4f9a-b58e-bdc446d7d952
ef7bd1df-a398-4582-854e-4b1966def010
0537afee-9556-4a34-ba5f-f38019d06a2c
f36a0897-38e9-4314-b649-5b3ae3ba02b3
2baeb097-33ff-4a55-aed3-2aa3b06af554
7b9d7ed2-57ee-428b-9ad7-625188d40c09
43369688-9b92-4d59-92b1-ef34f18295a4
1fabc346-1e51-41a6-a178-ad3aff239d74
e9a949e6-6035-4646-847b-1fea893e521a
54443ee0-90a3-4ca8-9a23-146dc7f41667

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: