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)

019cf7d1-596b-726b-949d-8183dea551f5
019cf7d1-596b-73f8-a52e-3282c39fa263
019cf7d1-596b-7538-839e-75ce9ab07cf9
019cf7d1-596b-765b-8967-259255f739c0
019cf7d1-596b-7775-9d18-fa1fbdb1bda2
019cf7d1-596b-788c-ae22-16899e75638d
019cf7d1-596b-79a6-bab9-d217f61c904b
019cf7d1-596b-7ac5-b31f-4258e427a70a
019cf7d1-596b-7be4-a648-16576d398d9d
019cf7d1-596b-7cfe-895a-77acb4a6b6a7
019cf7d1-596c-703e-a5ed-1bbe42aa22a8
019cf7d1-596c-7169-957f-b5bf11ae2595
019cf7d1-596c-7284-849e-fe7d964bca1e
019cf7d1-596c-739e-993a-cf00936866be
019cf7d1-596c-74b5-8d6e-281d9b238417

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)

1f121627-5365-6a06-8f26-4cf95d479851
1f121627-5365-6b96-8f26-4cf95d479851
1f121627-5365-6c72-8f26-4cf95d479851
1f121627-5365-6d44-8f26-4cf95d479851
1f121627-5365-6e0c-8f26-4cf95d479851
1f121627-5365-6eca-8f26-4cf95d479851
1f121627-5365-6f92-8f26-4cf95d479851
1f121627-5366-6050-8f26-4cf95d479851
1f121627-5366-610e-8f26-4cf95d479851
1f121627-5366-61cc-8f26-4cf95d479851
1f121627-5366-6302-8f26-4cf95d479851
1f121627-5366-63ca-8f26-4cf95d479851
1f121627-5366-647e-8f26-4cf95d479851
1f121627-5366-653c-8f26-4cf95d479851
1f121627-5366-65fa-8f26-4cf95d479851

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)

ec0a46c9-7011-4f59-80dc-001c7b2eab8f
cab26de6-d964-4e72-bcc1-769056db769a
1a074c7c-c8f1-48cf-9a3c-b4d27717f3af
b7e3e8d5-a3ef-4783-a854-1fa7bcd5c063
10f46c7b-3603-472a-ad39-c90c85c56cfb
34f1d695-772d-4d88-af29-91c00147f7c4
fb1473f5-04fb-4c5d-95b9-c2459cce0477
a1dfdc68-3110-4ff8-8bc6-0309f314cae8
0dcdfd20-46bb-4f56-bb60-a2cd199a14f6
c17e1739-befa-496d-90de-4225e6d7eebc
fb321378-0eeb-4216-b95f-01cb173868cc
27253dc4-1aa6-406d-8483-b8472b5e4a6f
08892c54-4c34-4ab0-ad12-c643d202e70d
c02618c8-083b-4f9f-9500-e73393e4693b
708dfe63-5a01-4647-80ad-58a44afa1140

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)

75366b0e-2162-11f1-8f26-4cf95d479851
75366b72-2162-11f1-8f26-4cf95d479851
75366bcc-2162-11f1-8f26-4cf95d479851
75366c30-2162-11f1-8f26-4cf95d479851
75366c9e-2162-11f1-8f26-4cf95d479851
75366cf8-2162-11f1-8f26-4cf95d479851
75366d5c-2162-11f1-8f26-4cf95d479851
75366db6-2162-11f1-8f26-4cf95d479851
75366e10-2162-11f1-8f26-4cf95d479851
75366e6a-2162-11f1-8f26-4cf95d479851
75366ece-2162-11f1-8f26-4cf95d479851
75366f28-2162-11f1-8f26-4cf95d479851
75366f82-2162-11f1-8f26-4cf95d479851
75366fe6-2162-11f1-8f26-4cf95d479851
75367040-2162-11f1-8f26-4cf95d479851

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)

4fc83826-3c04-8b04-87ea-5ce32bd83b97
90bd3926-3c04-8b04-87ea-5ce32bd83b97
65473a26-3c04-8b04-87ea-5ce32bd83b97
00823b26-3c04-8b04-87ea-5ce32bd83b97
7bd23c26-3c04-8b04-87ea-5ce32bd83b97
c8653e26-3c04-8b04-87ea-5ce32bd83b97
30323f26-3c04-8b04-87ea-5ce32bd83b97
30754026-3c04-8b04-87ea-5ce32bd83b97
d81d4126-3c04-8b04-87ea-5ce32bd83b97
5ed64226-3c04-8b04-87ea-5ce32bd83b97
eadc4326-3c04-8b04-87ea-5ce32bd83b97
aae34426-3c04-8b04-87ea-5ce32bd83b97
11444526-3c04-8b04-87ea-5ce32bd83b97
58964626-3c04-8b04-87ea-5ce32bd83b97
c04a4726-3c04-8b04-87ea-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: