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)

019dd639-bec8-7cc1-b2c9-a783e73e249a
019dd639-bec8-7e52-ae9d-80ab3020cb5c
019dd639-bec8-7f9a-b180-dd1ac2723771
019dd639-bec9-70b9-8b3e-39c5ff07e782
019dd639-bec9-71d8-ad77-14e640d20f5a
019dd639-bec9-72f2-a6c3-a91d4d1134a6
019dd639-bec9-740d-83db-583d8dffaa84
019dd639-bec9-7527-bbba-aa6a4a530377
019dd639-bec9-763e-9d9a-376e46c6a470
019dd639-bec9-7759-93b2-0806ad6643e5
019dd639-bec9-7873-93b4-51048359085c
019dd639-bec9-798e-96bf-bf02bb09b772
019dd639-bec9-7afe-9d58-a7d0955f059c
019dd639-bec9-7c5b-a2a4-6ab1c5d993ca
019dd639-bec9-7d7d-ac5b-44b3b10c52fd

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)

1f143524-32df-6066-90bd-4cf95d479851
1f143524-32df-6228-90bd-4cf95d479851
1f143524-32df-6304-90bd-4cf95d479851
1f143524-32df-63e0-90bd-4cf95d479851
1f143524-32df-64a8-90bd-4cf95d479851
1f143524-32df-6566-90bd-4cf95d479851
1f143524-32df-662e-90bd-4cf95d479851
1f143524-32df-66f6-90bd-4cf95d479851
1f143524-32df-67b4-90bd-4cf95d479851
1f143524-32df-687c-90bd-4cf95d479851
1f143524-32df-69d0-90bd-4cf95d479851
1f143524-32df-6aac-90bd-4cf95d479851
1f143524-32df-6b6a-90bd-4cf95d479851
1f143524-32df-6c32-90bd-4cf95d479851
1f143524-32df-6cf0-90bd-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)

decafeae-4e83-48d4-8024-b8e1d37244f6
a0acb35f-6f40-4733-9542-f30c26183365
19b01512-5413-4bbf-b64c-b9bf58737b1c
f2dc1e3e-55e0-43aa-bcb5-b68f39d44b97
2bb7dbf8-119c-4617-b79d-3b22c4e639cb
b2d29b62-d88b-4e26-93c6-fe16f006531d
1f673804-4975-411a-98fa-8a224b11fc8a
7c9bd12f-c149-4556-b87a-9b707d7ba62c
4ad74009-3cfe-4e18-b03b-c0a3c9dbc4cd
cd29cb2c-aed1-468c-8cea-b35f48c5b441
9cd36bf1-344a-41a0-8d94-604c9ad8a58d
09548576-cf82-4c9b-96ae-ca6cea8a133d
bd73b17f-84cd-42df-b903-f65728b0974c
d69caf8e-df0e-4d62-a281-caeb4a9e29b1
3c05675c-f47f-45fb-b7e0-ca7cdb4c2a0e

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)

432e0218-4352-11f1-90bd-4cf95d479851
432e027c-4352-11f1-90bd-4cf95d479851
432e02d6-4352-11f1-90bd-4cf95d479851
432e033a-4352-11f1-90bd-4cf95d479851
432e0394-4352-11f1-90bd-4cf95d479851
432e0402-4352-11f1-90bd-4cf95d479851
432e045c-4352-11f1-90bd-4cf95d479851
432e04b6-4352-11f1-90bd-4cf95d479851
432e051a-4352-11f1-90bd-4cf95d479851
432e0574-4352-11f1-90bd-4cf95d479851
432e05d8-4352-11f1-90bd-4cf95d479851
432e063c-4352-11f1-90bd-4cf95d479851
432e06a0-4352-11f1-90bd-4cf95d479851
432e06fa-4352-11f1-90bd-4cf95d479851
432e075e-4352-11f1-90bd-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)

310fdd15-4a05-8607-87ea-5ce32bd83b97
8fa8de15-4a05-8607-87ea-5ce32bd83b97
08a2df15-4a05-8607-87ea-5ce32bd83b97
175ae015-4a05-8607-87ea-5ce32bd83b97
ac8ce115-4a05-8607-87ea-5ce32bd83b97
207ee215-4a05-8607-87ea-5ce32bd83b97
13a0e315-4a05-8607-87ea-5ce32bd83b97
2b85e415-4a05-8607-87ea-5ce32bd83b97
c4ffe515-4a05-8607-87ea-5ce32bd83b97
f2d2e615-4a05-8607-87ea-5ce32bd83b97
6ff9e815-4a05-8607-87ea-5ce32bd83b97
d985e915-4a05-8607-87ea-5ce32bd83b97
610eea15-4a05-8607-87ea-5ce32bd83b97
d086eb15-4a05-8607-87ea-5ce32bd83b97
630cec15-4a05-8607-87ea-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: