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)

01a114d2-3d65-7488-95b8-1cf50c72511c
01a114d2-3d65-7621-a13e-250345c84b51
01a114d2-3d65-775d-b6e5-f50cc52f84b7
01a114d2-3d65-7877-ac0f-dcdb506c7dad
01a114d2-3d65-7992-8006-4c6a0164ce7f
01a114d2-3d65-7aa8-af77-5c7c08a41f51
01a114d2-3d65-7bbf-b834-3e547d5ddf9e
01a114d2-3d65-7cd5-b6e2-bfb14dde234a
01a114d2-3d65-7de8-a2b8-522666dfd8d9
01a114d2-3d65-7efe-855e-c827cc59b713
01a114d2-3d66-7011-a336-6fd077503d14
01a114d2-3d66-7134-8a21-9855d301c8b6
01a114d2-3d66-724e-9b88-9bab4e162974
01a114d2-3d66-7365-b234-489bb0bba348
01a114d2-3d66-747b-8e2f-b0543f6ece6f

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)

1f1c20f6-7ffb-60c8-b0c5-4cf95d479851
1f1c20f6-7ffb-6276-b0c5-4cf95d479851
1f1c20f6-7ffb-6366-b0c5-4cf95d479851
1f1c20f6-7ffb-6438-b0c5-4cf95d479851
1f1c20f6-7ffb-6500-b0c5-4cf95d479851
1f1c20f6-7ffb-65c8-b0c5-4cf95d479851
1f1c20f6-7ffb-6690-b0c5-4cf95d479851
1f1c20f6-7ffb-6758-b0c5-4cf95d479851
1f1c20f6-7ffb-6816-b0c5-4cf95d479851
1f1c20f6-7ffb-68de-b0c5-4cf95d479851
1f1c20f6-7ffb-6a28-b0c5-4cf95d479851
1f1c20f6-7ffb-6b04-b0c5-4cf95d479851
1f1c20f6-7ffb-6bc2-b0c5-4cf95d479851
1f1c20f6-7ffb-6c94-b0c5-4cf95d479851
1f1c20f6-7ffb-6d52-b0c5-4cf95d479851

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)

67ffbe24-c20f-11f1-b0c5-4cf95d479851
67ffbe88-c20f-11f1-b0c5-4cf95d479851
67ffbef6-c20f-11f1-b0c5-4cf95d479851
67ffbf6e-c20f-11f1-b0c5-4cf95d479851
67ffbfd2-c20f-11f1-b0c5-4cf95d479851
67ffc040-c20f-11f1-b0c5-4cf95d479851
67ffc0b8-c20f-11f1-b0c5-4cf95d479851
67ffc126-c20f-11f1-b0c5-4cf95d479851
67ffc18a-c20f-11f1-b0c5-4cf95d479851
67ffc1f8-c20f-11f1-b0c5-4cf95d479851
67ffc25c-c20f-11f1-b0c5-4cf95d479851
67ffc2b6-c20f-11f1-b0c5-4cf95d479851
67ffc324-c20f-11f1-b0c5-4cf95d479851
67ffc37e-c20f-11f1-b0c5-4cf95d479851
67ffc3e2-c20f-11f1-b0c5-4cf95d479851

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)

3679082d-4501-8811-87ea-5ce32bd83b97
03b3092d-4501-8811-87ea-5ce32bd83b97
08540a2d-4501-8811-87ea-5ce32bd83b97
46b80b2d-4501-8811-87ea-5ce32bd83b97
f45d0c2d-4501-8811-87ea-5ce32bd83b97
31640d2d-4501-8811-87ea-5ce32bd83b97
1cd00e2d-4501-8811-87ea-5ce32bd83b97
26300f2d-4501-8811-87ea-5ce32bd83b97
afde102d-4501-8811-87ea-5ce32bd83b97
db37112d-4501-8811-87ea-5ce32bd83b97
6971122d-4501-8811-87ea-5ce32bd83b97
b2c4132d-4501-8811-87ea-5ce32bd83b97
7e5e142d-4501-8811-87ea-5ce32bd83b97
7ac0152d-4501-8811-87ea-5ce32bd83b97
c068162d-4501-8811-87ea-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)

b3f316c0-228b-41b9-a339-4cd00f166f70
bfaad186-8305-4143-8b38-05e5745346ee
dd48f7b9-2d9a-4605-82c3-3b5a8c9b6a1e
1c8aac91-a5c0-4d48-b3f8-4fded5bbdce5
d22a7eef-7658-4e99-88f5-6865b6725e10
f7d71f98-45ba-482d-92c1-61bf529b46aa
51a0f14f-5bcf-432a-ac88-806476cdee9b
d30cddbd-e97d-4ce7-8670-5cdb6a1d32e9
12f3abba-d8a0-4059-9dc6-30d459755138
9ce4149a-d8b3-466e-a81a-c6f4f6499e91
11025013-5cbc-42ea-8e92-ac83a7ca4bb2
e5c5b762-70fe-42a8-9da9-478bdf3ea5c3
875a2514-1517-4ad9-8ad5-588ec239a2d0
35c24e5b-e3c0-491b-a90d-b9b40294a86a
7038d8da-912a-4b49-9379-6f09565800dd

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: