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)

01a1a558-100c-7ac5-bdfb-b2dbaf0aa878
01a1a558-100c-7cb1-a32f-849a80d73a3c
01a1a558-100c-7e21-bcaa-f64c25d20d97
01a1a558-100c-7f6d-91b6-d3e06dc72199
01a1a558-100d-70a8-a04a-677a8a9788ff
01a1a558-100d-71e4-aaec-a2bb6aac93a4
01a1a558-100d-731b-b362-722b1cdfffaf
01a1a558-100d-7400-9f82-4871c2d03a05
01a1a558-100d-753c-85f4-928f31e817da
01a1a558-100d-767b-9d33-f3ee62481176
01a1a558-100d-77b3-9d38-6b44eab47444
01a1a558-100d-78ee-8b9a-03571970fb99
01a1a558-100d-7a25-b29d-593de9b24ab2
01a1a558-100d-7b5d-b4d2-5994839ada3c
01a1a558-100d-7c98-aec0-cedb886275af

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)

1f1d81cd-3746-61b4-a34a-4cf95d479851
1f1d81cd-3746-643e-a34a-4cf95d479851
1f1d81cd-3746-65ba-a34a-4cf95d479851
1f1d81cd-3746-6718-a34a-4cf95d479851
1f1d81cd-3746-6862-a34a-4cf95d479851
1f1d81cd-3746-69b6-a34a-4cf95d479851
1f1d81cd-3746-6b00-a34a-4cf95d479851
1f1d81cd-3746-6c4a-a34a-4cf95d479851
1f1d81cd-3746-6d9e-a34a-4cf95d479851
1f1d81cd-3746-6ee8-a34a-4cf95d479851
1f1d81cd-3747-60e6-a34a-4cf95d479851
1f1d81cd-3747-6244-a34a-4cf95d479851
1f1d81cd-3747-638e-a34a-4cf95d479851
1f1d81cd-3747-64d8-a34a-4cf95d479851
1f1d81cd-3747-662c-a34a-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)

d3747794-d81c-11f1-a34a-4cf95d479851
d3747820-d81c-11f1-a34a-4cf95d479851
d37478b6-d81c-11f1-a34a-4cf95d479851
d374794c-d81c-11f1-a34a-4cf95d479851
d37479e2-d81c-11f1-a34a-4cf95d479851
d3747a6e-d81c-11f1-a34a-4cf95d479851
d3747afa-d81c-11f1-a34a-4cf95d479851
d3747b86-d81c-11f1-a34a-4cf95d479851
d3747c1c-d81c-11f1-a34a-4cf95d479851
d3747cb2-d81c-11f1-a34a-4cf95d479851
d3747d3e-d81c-11f1-a34a-4cf95d479851
d3747dca-d81c-11f1-a34a-4cf95d479851
d3747e60-d81c-11f1-a34a-4cf95d479851
d3747eec-d81c-11f1-a34a-4cf95d479851
d3747f82-d81c-11f1-a34a-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)

04cf590e-a101-8413-87ea-5ce32bd83b97
ce045a0e-a101-8413-87ea-5ce32bd83b97
42465c0e-a101-8413-87ea-5ce32bd83b97
fab95d0e-a101-8413-87ea-5ce32bd83b97
ed2f5e0e-a101-8413-87ea-5ce32bd83b97
0a4e5f0e-a101-8413-87ea-5ce32bd83b97
d04c600e-a101-8413-87ea-5ce32bd83b97
17c0610e-a101-8413-87ea-5ce32bd83b97
940d620e-a101-8413-87ea-5ce32bd83b97
79a3630e-a101-8413-87ea-5ce32bd83b97
e2e5640e-a101-8413-87ea-5ce32bd83b97
a62f650e-a101-8413-87ea-5ce32bd83b97
1d15660e-a101-8413-87ea-5ce32bd83b97
6582670e-a101-8413-87ea-5ce32bd83b97
e9a5680e-a101-8413-87ea-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)

1c4fb06f-9c8a-490d-b315-257885b55c6d
5617b08f-14fd-44fe-b305-fa5423c7561a
9150244f-b25f-4745-b9ca-497123f5a0fc
3815891d-5b26-43a3-8bfe-d9b9391791ae
11fc35e1-aae5-4efd-8701-ded0dcd4005a
f30f5278-c0b6-40a6-9abe-5e9b4047d00a
edf160bd-55a9-402b-8ff6-f0e35de509e4
34043edb-3e14-4674-95b1-ddbba578c307
5fdb0bcb-4f1c-436b-9e38-36a71bb2b7ff
010571e8-d0c9-43f9-8818-5921a2956e83
9ee079df-23ad-4343-857d-a319797c5e9d
1365e65b-17f1-44f1-8254-e7bd6425dd02
260942d3-3b74-4360-9ef5-73f13be189f5
5401188e-e7f7-4bf1-9289-34d3e7313242
c35a2b6b-b8dc-43b4-8a0b-849fa44509ae

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: