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)

01a12f5a-6e24-7740-959f-a89fa52c742f
01a12f5a-6e24-7913-9c91-5ad3725843cb
01a12f5a-6e24-7a52-9ce5-5d20a6b90e42
01a12f5a-6e24-7b6d-8d30-8fc24b6910bf
01a12f5a-6e24-7c84-af9d-bb230035942c
01a12f5a-6e24-7da2-99ad-a78dcf34765c
01a12f5a-6e24-7eb1-91b1-4947a0da6121
01a12f5a-6e24-7fc3-9349-7fd14f781141
01a12f5a-6e25-70d5-90a3-e129cf996d00
01a12f5a-6e25-71e8-bb8f-d73d4aa19afb
01a12f5a-6e25-72fa-a225-c6f1abe2537c
01a12f5a-6e25-74c9-8dcb-0841f0fc22a0
01a12f5a-6e25-75e4-8455-98d2adb976b2
01a12f5a-6e25-76f6-ba96-c0e21eed81e7
01a12f5a-6e25-7809-a940-40feeccf4b02

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)

1f1c61bc-fefd-6f04-9fd2-4cf95d479851
1f1c61bc-fefe-60da-9fd2-4cf95d479851
1f1c61bc-fefe-61b6-9fd2-4cf95d479851
1f1c61bc-fefe-627e-9fd2-4cf95d479851
1f1c61bc-fefe-6346-9fd2-4cf95d479851
1f1c61bc-fefe-640e-9fd2-4cf95d479851
1f1c61bc-fefe-64cc-9fd2-4cf95d479851
1f1c61bc-fefe-658a-9fd2-4cf95d479851
1f1c61bc-fefe-6648-9fd2-4cf95d479851
1f1c61bc-fefe-6710-9fd2-4cf95d479851
1f1c61bc-fefe-688c-9fd2-4cf95d479851
1f1c61bc-fefe-69e0-9fd2-4cf95d479851
1f1c61bc-fefe-6b16-9fd2-4cf95d479851
1f1c61bc-fefe-6bfc-9fd2-4cf95d479851
1f1c61bc-fefe-6cba-9fd2-4cf95d479851

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)

cfefed96-c61b-11f1-9fd2-4cf95d479851
cfefedfa-c61b-11f1-9fd2-4cf95d479851
cfefee5e-c61b-11f1-9fd2-4cf95d479851
cfefeec2-c61b-11f1-9fd2-4cf95d479851
cfefef26-c61b-11f1-9fd2-4cf95d479851
cfefef8a-c61b-11f1-9fd2-4cf95d479851
cfefefee-c61b-11f1-9fd2-4cf95d479851
cfeff052-c61b-11f1-9fd2-4cf95d479851
cfeff0b6-c61b-11f1-9fd2-4cf95d479851
cfeff11a-c61b-11f1-9fd2-4cf95d479851
cfeff188-c61b-11f1-9fd2-4cf95d479851
cfeff1ec-c61b-11f1-9fd2-4cf95d479851
cfeff250-c61b-11f1-9fd2-4cf95d479851
cfeff2be-c61b-11f1-9fd2-4cf95d479851
cfeff322-c61b-11f1-9fd2-4cf95d479851

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)

62350626-2002-8d11-87ea-5ce32bd83b97
fd720726-2002-8d11-87ea-5ce32bd83b97
35650826-2002-8d11-87ea-5ce32bd83b97
18c40926-2002-8d11-87ea-5ce32bd83b97
29070a26-2002-8d11-87ea-5ce32bd83b97
319b0b26-2002-8d11-87ea-5ce32bd83b97
8c730c26-2002-8d11-87ea-5ce32bd83b97
ac490d26-2002-8d11-87ea-5ce32bd83b97
19aa0e26-2002-8d11-87ea-5ce32bd83b97
38ae0f26-2002-8d11-87ea-5ce32bd83b97
cae21026-2002-8d11-87ea-5ce32bd83b97
c1581126-2002-8d11-87ea-5ce32bd83b97
67fa1226-2002-8d11-87ea-5ce32bd83b97
4f521326-2002-8d11-87ea-5ce32bd83b97
f3a01426-2002-8d11-87ea-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)

350aaa5e-511b-452c-abe7-79b00b3da7fc
dbc8f607-458e-4d33-951f-eab69d08e22d
4f891c4f-0fde-436b-9a51-b0fa62eca5a8
2a591e89-6823-452a-9a8c-b54159166257
4cf03c18-8577-4690-850f-d87430d155ce
e5218218-4c01-4e99-8ea0-ef59c58e1f4c
fbbcc221-4c04-40be-9ccf-7dbb0879a8c7
be2596a0-282b-4722-90bb-06c817b262dc
4dcace71-2436-4823-86da-bf984628893d
c51518a0-0f58-4d86-ba5b-07d3594dc31f
9de50a29-57c2-4284-9de5-f3328ad34d80
d4d5db13-1624-4b0a-a71d-4344232364cc
28ed6692-f38a-44eb-9bd5-da6740a9dee4
6d3b0884-0f0a-40b2-a91e-0e073c9c5c04
f439158a-afb4-4fdc-b3b8-1829b7858df5

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: