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)

019d14ac-9a5a-7411-a9b3-67d4df370d1a
019d14ac-9a5a-75cb-8566-8ddd447b7336
019d14ac-9a5a-7717-bf90-7da478844fa9
019d14ac-9a5a-783a-af2d-6f0c56cd90a4
019d14ac-9a5a-7954-aac4-4f6c1ee74be0
019d14ac-9a5a-7a6f-a4be-4802509ecb3b
019d14ac-9a5a-7b8a-a2eb-3b70fda86c96
019d14ac-9a5a-7ca4-b781-f54d98975c4c
019d14ac-9a5a-7dbb-a2d5-a5a9ed712596
019d14ac-9a5a-7ed1-9f69-feb60fa05a18
019d14ac-9a5a-7fe8-8f97-f6f236f28b7f
019d14ac-9a5b-70fe-b8ba-a17a31778489
019d14ac-9a5b-7215-86f2-d5f26cfd4d47
019d14ac-9a5b-7330-9a37-220fdb262d27
019d14ac-9a5b-7446-8619-74c4968ffb94

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)

1f125c9a-9ced-617e-9cc5-4cf95d479851
1f125c9a-9ced-6318-9cc5-4cf95d479851
1f125c9a-9ced-63fe-9cc5-4cf95d479851
1f125c9a-9ced-64d0-9cc5-4cf95d479851
1f125c9a-9ced-6598-9cc5-4cf95d479851
1f125c9a-9ced-6656-9cc5-4cf95d479851
1f125c9a-9ced-671e-9cc5-4cf95d479851
1f125c9a-9ced-67dc-9cc5-4cf95d479851
1f125c9a-9ced-689a-9cc5-4cf95d479851
1f125c9a-9ced-6958-9cc5-4cf95d479851
1f125c9a-9ced-6aa2-9cc5-4cf95d479851
1f125c9a-9ced-6b6a-9cc5-4cf95d479851
1f125c9a-9ced-6c28-9cc5-4cf95d479851
1f125c9a-9ced-6ce6-9cc5-4cf95d479851
1f125c9a-9ced-6d9a-9cc5-4cf95d479851

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)

1704fe8f-2e7c-4a5a-b34a-6ff327ce1c59
b4584666-b56c-457b-b5b9-81939eba8764
a93e1b6f-5eed-4fb8-aca3-1a68ba41f3d4
2b8c26dd-4bd0-4636-85b7-2101d62f1780
96b98d8f-5512-45e8-814c-44ea0f9131d9
61250635-5c34-432b-8c09-2fa8201f3044
661020cd-adaa-4823-8302-bb8f516377bb
868bb765-77c7-4740-9333-2b11beae8687
df25981d-f9b5-4ea2-aa44-ef164e956660
76a962a2-1592-4e9b-af36-fdd461f8e299
c90ab0ec-8089-4bcf-b896-1e2045ee5414
99dca840-0acd-4c17-bdf7-95bc44e892f8
5a7cbda2-1e7b-496b-99b8-69dd5fb71a1c
45f5c752-33da-47b4-82dc-cb6c8a15c2d5
29b7535e-a99c-4b19-9c8b-f459fd7b6a1f

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)

a9cee2b8-25c9-11f1-9cc5-4cf95d479851
a9cee312-25c9-11f1-9cc5-4cf95d479851
a9cee380-25c9-11f1-9cc5-4cf95d479851
a9cee3e4-25c9-11f1-9cc5-4cf95d479851
a9cee43e-25c9-11f1-9cc5-4cf95d479851
a9cee4a2-25c9-11f1-9cc5-4cf95d479851
a9cee4fc-25c9-11f1-9cc5-4cf95d479851
a9cee556-25c9-11f1-9cc5-4cf95d479851
a9cee5ba-25c9-11f1-9cc5-4cf95d479851
a9cee61e-25c9-11f1-9cc5-4cf95d479851
a9cee682-25c9-11f1-9cc5-4cf95d479851
a9cee6e6-25c9-11f1-9cc5-4cf95d479851
a9cee740-25c9-11f1-9cc5-4cf95d479851
a9cee79a-25c9-11f1-9cc5-4cf95d479851
a9cee7fe-25c9-11f1-9cc5-4cf95d479851

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)

7923461d-0102-8105-87ea-5ce32bd83b97
132b471d-0102-8105-87ea-5ce32bd83b97
7622481d-0102-8105-87ea-5ce32bd83b97
2a434a1d-0102-8105-87ea-5ce32bd83b97
d3eb4b1d-0102-8105-87ea-5ce32bd83b97
dab34c1d-0102-8105-87ea-5ce32bd83b97
41bc4d1d-0102-8105-87ea-5ce32bd83b97
e2704e1d-0102-8105-87ea-5ce32bd83b97
dc1c4f1d-0102-8105-87ea-5ce32bd83b97
0dd0501d-0102-8105-87ea-5ce32bd83b97
7ef9511d-0102-8105-87ea-5ce32bd83b97
f6b2521d-0102-8105-87ea-5ce32bd83b97
3a38531d-0102-8105-87ea-5ce32bd83b97
02ec541d-0102-8105-87ea-5ce32bd83b97
142e551d-0102-8105-87ea-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: