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)

019c107b-d515-750f-83af-4ad6faa0b819
019c107b-d515-7782-96b1-5b6d0c8c190a
019c107b-d515-790f-b3b1-4085f33c229e
019c107b-d515-7a7f-b41a-7345c63cb9fd
019c107b-d515-7bf0-b0da-5011b844932d
019c107b-d515-7d61-877e-ca8f98468c9b
019c107b-d515-7ecd-9052-68d094be9283
019c107b-d516-7036-bf84-08bfafa3a931
019c107b-d516-71a2-946c-c0f41cda9939
019c107b-d516-730f-b11e-9586727ad206
019c107b-d516-747f-891b-9970bde18a68
019c107b-d516-75ec-9f92-00d06e641342
019c107b-d516-7765-91d7-82462afd9860
019c107b-d516-78d5-afcf-33f3235bd6e1
019c107b-d516-7a42-bf99-2b31001d52ff

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)

1f0fe15f-8b50-6956-8516-4cf95d479851
1f0fe15f-8b50-6c12-8516-4cf95d479851
1f0fe15f-8b50-6df2-8516-4cf95d479851
1f0fe15f-8b50-6f96-8516-4cf95d479851
1f0fe15f-8b51-6126-8516-4cf95d479851
1f0fe15f-8b51-62b6-8516-4cf95d479851
1f0fe15f-8b51-643c-8516-4cf95d479851
1f0fe15f-8b51-65cc-8516-4cf95d479851
1f0fe15f-8b51-6752-8516-4cf95d479851
1f0fe15f-8b51-68d8-8516-4cf95d479851
1f0fe15f-8b51-6b12-8516-4cf95d479851
1f0fe15f-8b51-6cc0-8516-4cf95d479851
1f0fe15f-8b51-6e46-8516-4cf95d479851
1f0fe15f-8b51-6fcc-8516-4cf95d479851
1f0fe15f-8b52-61e8-8516-4cf95d479851

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)

aa4c563f-3a2d-4fac-91d5-da01013df353
5b8e7b8c-a17c-4351-9d8d-696e725381af
c318a5db-583a-456d-b48f-efe97d7bf7b7
1a49def0-a5a6-46f1-9f96-d1c121a72ec8
e792707f-e3ff-47bf-9cd3-26c4121b2691
9622557b-ab28-4f11-869b-d400aaad88fa
3cfad39e-7aef-4c03-9544-7d5112a61965
73d8edb3-7eaf-4ec7-910a-cb6fda47266c
04e71a3d-3bf5-4757-a4a2-064748c05acb
fd066e33-c39e-4d83-8d93-050e0d5d81e7
300a3f92-2c8a-4113-969a-9b7b6a1e30bb
5dcb219b-8209-40d0-b0b9-46001b0f0680
eafb4ced-3bc7-4b34-95c9-a9615f49de60
74ca801d-2dde-411b-99be-2d1299749017
d21c0591-fdf6-48f8-948d-7be2cee9093d

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)

f8b52968-fe15-11f0-8516-4cf95d479851
f8b52a12-fe15-11f0-8516-4cf95d479851
f8b52aa8-fe15-11f0-8516-4cf95d479851
f8b52b48-fe15-11f0-8516-4cf95d479851
f8b52bde-fe15-11f0-8516-4cf95d479851
f8b52c7e-fe15-11f0-8516-4cf95d479851
f8b52d28-fe15-11f0-8516-4cf95d479851
f8b52dc8-fe15-11f0-8516-4cf95d479851
f8b52e68-fe15-11f0-8516-4cf95d479851
f8b52efe-fe15-11f0-8516-4cf95d479851
f8b52f9e-fe15-11f0-8516-4cf95d479851
f8b53048-fe15-11f0-8516-4cf95d479851
f8b530e8-fe15-11f0-8516-4cf95d479851
f8b5317e-fe15-11f0-8516-4cf95d479851
f8b53214-fe15-11f0-8516-4cf95d479851

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)

c5dae238-ae04-8e01-87ea-5ce32bd83b97
8ce0e438-ae04-8e01-87ea-5ce32bd83b97
0256e538-ae04-8e01-87ea-5ce32bd83b97
31d3e638-ae04-8e01-87ea-5ce32bd83b97
a5c4e738-ae04-8e01-87ea-5ce32bd83b97
1a4fe838-ae04-8e01-87ea-5ce32bd83b97
77ede938-ae04-8e01-87ea-5ce32bd83b97
4b18ea38-ae04-8e01-87ea-5ce32bd83b97
ed97eb38-ae04-8e01-87ea-5ce32bd83b97
ae99ec38-ae04-8e01-87ea-5ce32bd83b97
7ef8ed38-ae04-8e01-87ea-5ce32bd83b97
844fee38-ae04-8e01-87ea-5ce32bd83b97
f6d1ef38-ae04-8e01-87ea-5ce32bd83b97
7be6f038-ae04-8e01-87ea-5ce32bd83b97
7c45f138-ae04-8e01-87ea-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: