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)

019fe2b5-d19c-70e6-98f5-3434251c4530
019fe2b5-d19c-73c7-aebe-3e8b9aa0b453
019fe2b5-d19c-7538-b507-f342013ad12f
019fe2b5-d19c-7657-838c-c3cbb2626211
019fe2b5-d19c-7771-9201-923ae5dcb32c
019fe2b5-d19c-7888-9ce2-5f1d0e13bc8e
019fe2b5-d19c-799a-b999-ad7152193559
019fe2b5-d19c-7aad-b1e6-260149a750a1
019fe2b5-d19c-7bbf-9d7e-8b8bdcb850be
019fe2b5-d19c-7cd5-8e23-8fa833b5619f
019fe2b5-d19c-7dec-a678-c3ba4d2cea0b
019fe2b5-d19c-7efe-8db7-fe538e4fdf0f
019fe2b5-d19d-7011-9aff-64dde0f7ac94
019fe2b5-d19d-7127-9d2b-9936a21ca013
019fe2b5-d19d-723a-830b-ded43c4560ca

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)

1f19359f-1cd4-6e94-b458-4cf95d479851
1f19359f-1cd5-6092-b458-4cf95d479851
1f19359f-1cd5-6182-b458-4cf95d479851
1f19359f-1cd5-624a-b458-4cf95d479851
1f19359f-1cd5-6312-b458-4cf95d479851
1f19359f-1cd5-63d0-b458-4cf95d479851
1f19359f-1cd5-648e-b458-4cf95d479851
1f19359f-1cd5-6556-b458-4cf95d479851
1f19359f-1cd5-6614-b458-4cf95d479851
1f19359f-1cd5-66dc-b458-4cf95d479851
1f19359f-1cd5-6858-b458-4cf95d479851
1f19359f-1cd5-692a-b458-4cf95d479851
1f19359f-1cd5-69e8-b458-4cf95d479851
1f19359f-1cd5-6aba-b458-4cf95d479851
1f19359f-1cd5-6b78-b458-4cf95d479851

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)

f1cd5c54-9359-11f1-b458-4cf95d479851
f1cd5cb8-9359-11f1-b458-4cf95d479851
f1cd5d1c-9359-11f1-b458-4cf95d479851
f1cd5d80-9359-11f1-b458-4cf95d479851
f1cd5de4-9359-11f1-b458-4cf95d479851
f1cd5e3e-9359-11f1-b458-4cf95d479851
f1cd5ea2-9359-11f1-b458-4cf95d479851
f1cd5f06-9359-11f1-b458-4cf95d479851
f1cd5f6a-9359-11f1-b458-4cf95d479851
f1cd5fce-9359-11f1-b458-4cf95d479851
f1cd6028-9359-11f1-b458-4cf95d479851
f1cd608c-9359-11f1-b458-4cf95d479851
f1cd60f0-9359-11f1-b458-4cf95d479851
f1cd614a-9359-11f1-b458-4cf95d479851
f1cd61b8-9359-11f1-b458-4cf95d479851

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)

38f85536-6a04-8c0d-87ea-5ce32bd83b97
69695636-6a04-8c0d-87ea-5ce32bd83b97
d7a45736-6a04-8c0d-87ea-5ce32bd83b97
c4f35836-6a04-8c0d-87ea-5ce32bd83b97
3e535936-6a04-8c0d-87ea-5ce32bd83b97
ae685a36-6a04-8c0d-87ea-5ce32bd83b97
42745b36-6a04-8c0d-87ea-5ce32bd83b97
ad345c36-6a04-8c0d-87ea-5ce32bd83b97
a8e85d36-6a04-8c0d-87ea-5ce32bd83b97
ea235e36-6a04-8c0d-87ea-5ce32bd83b97
53c45f36-6a04-8c0d-87ea-5ce32bd83b97
a7266036-6a04-8c0d-87ea-5ce32bd83b97
1d356236-6a04-8c0d-87ea-5ce32bd83b97
70e96336-6a04-8c0d-87ea-5ce32bd83b97
b5a26436-6a04-8c0d-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)

a69a9f15-d0b5-4a7d-bcdf-f264421f5e98
4bea5721-fd03-431d-b6f6-875dbc5bacc2
e2aa4777-eb16-4030-a1db-7c1e9c831cfd
72168e85-6898-43c9-a0eb-37a5439df8e2
cb9a9e61-3589-4da7-8944-c6531b9676b6
690269e6-f492-4ce6-b777-76d6f38725aa
f04ec666-bd61-4e01-838d-ba2644a86fd3
2f1fcc74-fccf-4d0f-811f-828943cd40fb
0cb64c58-8d7e-46b3-8de4-aa38dd6b1b13
7719e12b-e86e-4d2f-8871-9e2a648577e9
a6cfe807-4d11-4aaf-9025-24ef727645a5
613921e9-7c47-4e53-becb-02b8e2c2a969
cbb4114d-bfa1-47ff-b78e-3b9f8572cba2
4f238e2a-119f-4133-9cf4-3757b03b8529
fbbeb3d0-9cb9-4443-b0ec-9c6c38f1d41b

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: