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)

018f453d-3307-7be8-9ff0-72b5382cd51e
018f453d-3307-7dbf-b459-ec73c2075512
018f453d-3307-7f03-aa1f-db15dbbd3211
018f453d-3308-7025-b075-522bdc47a9b2
018f453d-3308-7144-b8aa-423215d6ab6b
018f453d-3308-725f-b34a-d4d8420520fe
018f453d-3308-7379-8018-415663871b62
018f453d-3308-7494-b9ce-23e2d1bb64bf
018f453d-3308-75af-a298-fda3b9e825a7
018f453d-3308-76cd-83a2-3926b37d151b
018f453d-3308-77e8-a21a-1ba4b54afe41
018f453d-3308-7903-a1fc-4677fb516085
018f453d-3308-7a1d-8094-fd29be3c63ce
018f453d-3308-7b4c-9c72-72da7297b05c
018f453d-3308-7c6b-b565-c90a9e7f097c

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)

1ef0a52b-a1ac-6c8e-9f63-4cf95d479851
1ef0a52b-a1ac-6e50-9f63-4cf95d479851
1ef0a52b-a1ac-6f36-9f63-4cf95d479851
1ef0a52b-a1ad-60c6-9f63-4cf95d479851
1ef0a52b-a1ad-61ac-9f63-4cf95d479851
1ef0a52b-a1ad-6274-9f63-4cf95d479851
1ef0a52b-a1ad-6332-9f63-4cf95d479851
1ef0a52b-a1ad-63fa-9f63-4cf95d479851
1ef0a52b-a1ad-64c2-9f63-4cf95d479851
1ef0a52b-a1ad-6580-9f63-4cf95d479851
1ef0a52b-a1ad-66c0-9f63-4cf95d479851
1ef0a52b-a1ad-6788-9f63-4cf95d479851
1ef0a52b-a1ad-683c-9f63-4cf95d479851
1ef0a52b-a1ad-6904-9f63-4cf95d479851
1ef0a52b-a1ad-69b8-9f63-4cf95d479851

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)

91dd94c9-64b9-4274-b4f3-fc726af745b4
16902e02-6d34-44ea-922b-6dae3b8a47d6
86c41429-b771-416a-83b4-a1c6e8472796
235cf00f-7b77-46c5-a259-2f0790b04328
e415d082-86d6-4a85-b3d1-14836d743917
8191c934-e00d-4721-bd51-ea4308c23d2a
b9fd73d6-508a-467f-80c6-eb18fe5d1ad7
03d4f1d6-0e38-4d42-a2f3-4034d0ac97c0
e65c071c-b384-4007-8eab-b6373fea665b
ab96b56f-4a3a-47cd-bace-17a4938c204b
a3366df9-dd11-46fb-892e-2eee5eb03bba
8c3f3fb3-8a79-4a92-857f-71b3c0cf3c9d
a3f5d438-d0fe-426e-a772-0ac1c3b6fdab
056c047c-9dd3-454b-89fe-06e4c15d5b5f
1e135469-61da-4e7a-af48-6da6e04a74a6

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)

ba1adee0-0a52-11ef-9f63-4cf95d479851
ba1adf44-0a52-11ef-9f63-4cf95d479851
ba1adfa8-0a52-11ef-9f63-4cf95d479851
ba1ae00c-0a52-11ef-9f63-4cf95d479851
ba1ae070-0a52-11ef-9f63-4cf95d479851
ba1ae0ca-0a52-11ef-9f63-4cf95d479851
ba1ae138-0a52-11ef-9f63-4cf95d479851
ba1ae1a6-0a52-11ef-9f63-4cf95d479851
ba1ae20a-0a52-11ef-9f63-4cf95d479851
ba1ae26e-0a52-11ef-9f63-4cf95d479851
ba1ae2c8-0a52-11ef-9f63-4cf95d479851
ba1ae32c-0a52-11ef-9f63-4cf95d479851
ba1ae386-0a52-11ef-9f63-4cf95d479851
ba1ae3d6-0a52-11ef-9f63-4cf95d479851
ba1ae430-0a52-11ef-9f63-4cf95d479851

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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

0d01c409-04be-807d-87e8-5ce32bd83b96
a3c2c509-04be-807d-87e8-5ce32bd83b96
963bc609-04be-807d-87e8-5ce32bd83b96
7d24c709-04be-807d-87e8-5ce32bd83b96
450fc809-04be-807d-87e8-5ce32bd83b96
63abca09-04be-807d-87e8-5ce32bd83b96
d0b5cb09-04be-807d-87e8-5ce32bd83b96
7452cc09-04be-807d-87e8-5ce32bd83b96
6c87cd09-04be-807d-87e8-5ce32bd83b96
39bace09-04be-807d-87e8-5ce32bd83b96
a284cf09-04be-807d-87e8-5ce32bd83b96
1a86d009-04be-807d-87e8-5ce32bd83b96
345cd109-04be-807d-87e8-5ce32bd83b96
2284d209-04be-807d-87e8-5ce32bd83b96
4fd4d309-04be-807d-87e8-5ce32bd83b96

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: