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)

019ad4e6-43fe-78a4-a389-67b991d2e2bf
019ad4e6-43fe-7a3a-aa48-4d489cf99439
019ad4e6-43fe-7bbb-8ee4-448e4d8f0000
019ad4e6-43fe-7cfa-b2e2-8fd73e3cf3d7
019ad4e6-43fe-7e19-ace2-bae9a6ade01b
019ad4e6-43fe-7f34-80b9-845ead31ef22
019ad4e6-43ff-704e-9c91-80f7179c9079
019ad4e6-43ff-7169-9b3a-6ad414d52114
019ad4e6-43ff-7284-9e40-af63cdf5cddf
019ad4e6-43ff-73a2-ab32-51d0d8c941dd
019ad4e6-43ff-74bd-9ec0-914ea1454e86
019ad4e6-43ff-75d3-890f-5d2806dc2f96
019ad4e6-43ff-76ee-b5ff-2e184117d096
019ad4e6-43ff-7809-8196-4572729d6677
019ad4e6-43ff-7923-b378-a6b51daa6a76

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)

1f0cdee7-6417-633a-92e2-4cf95d479851
1f0cdee7-6417-64d4-92e2-4cf95d479851
1f0cdee7-6417-65c4-92e2-4cf95d479851
1f0cdee7-6417-6d8a-92e2-4cf95d479851
1f0cdee7-6417-6e52-92e2-4cf95d479851
1f0cdee7-6417-6f1a-92e2-4cf95d479851
1f0cdee7-6417-6fe2-92e2-4cf95d479851
1f0cdee7-6418-6096-92e2-4cf95d479851
1f0cdee7-6418-6154-92e2-4cf95d479851
1f0cdee7-6418-621c-92e2-4cf95d479851
1f0cdee7-6418-635c-92e2-4cf95d479851
1f0cdee7-6418-642e-92e2-4cf95d479851
1f0cdee7-6418-64ec-92e2-4cf95d479851
1f0cdee7-6418-65aa-92e2-4cf95d479851
1f0cdee7-6418-6668-92e2-4cf95d479851

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)

4f8c9cee-a5b1-4b2e-8537-a62babf1975f
ea689d4f-83f0-4d6b-b0bf-f1874726c44f
2dcd1558-63e1-4d89-9727-d0691b5dbe05
76232110-d289-4e0d-b6ea-06dfef9aadfa
7e80c7c9-db12-4286-9c78-91c69e53c956
3a6f62dd-33cd-49cf-9ca3-e4c34a2f7ec9
e7bec712-0975-4b2d-b30a-292272fa9d4c
4ecac8b3-1c84-4458-9e71-e90954ccde11
d6234b3a-ffe1-4280-9ca9-0aa35a35c210
1f04c4fe-984c-436c-bf27-35929fb513df
e2169593-8770-4355-9db4-397d99ad8e21
e3dcd5e9-7acc-4a6c-a1e1-1c4820d574f4
52c55a40-353f-4a7f-9fd4-317ba05eeb6d
94b14890-cf1e-4d05-963f-db1f7acc5a7a
ddfcd30e-1d97-4af6-b64c-4e599a65fd9a

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)

76418b9a-cdee-11f0-92e2-4cf95d479851
76418bf4-cdee-11f0-92e2-4cf95d479851
76418c58-cdee-11f0-92e2-4cf95d479851
76418cbc-cdee-11f0-92e2-4cf95d479851
76418d20-cdee-11f0-92e2-4cf95d479851
76418d84-cdee-11f0-92e2-4cf95d479851
76418dde-cdee-11f0-92e2-4cf95d479851
76418e42-cdee-11f0-92e2-4cf95d479851
76418ea6-cdee-11f0-92e2-4cf95d479851
76418f14-cdee-11f0-92e2-4cf95d479851
76418f6e-cdee-11f0-92e2-4cf95d479851
76418fc8-cdee-11f0-92e2-4cf95d479851
7641902c-cdee-11f0-92e2-4cf95d479851
76419090-cdee-11f0-92e2-4cf95d479851
764190ea-cdee-11f0-92e2-4cf95d479851

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)

8604d60b-1b03-8e14-87e9-5ce32bd83b97
a3bfd70b-1b03-8e14-87e9-5ce32bd83b97
f0f6d80b-1b03-8e14-87e9-5ce32bd83b97
02a8d90b-1b03-8e14-87e9-5ce32bd83b97
c9e7da0b-1b03-8e14-87e9-5ce32bd83b97
6c29dc0b-1b03-8e14-87e9-5ce32bd83b97
4384dd0b-1b03-8e14-87e9-5ce32bd83b97
877dde0b-1b03-8e14-87e9-5ce32bd83b97
6346df0b-1b03-8e14-87e9-5ce32bd83b97
ae20e00b-1b03-8e14-87e9-5ce32bd83b97
c802e10b-1b03-8e14-87e9-5ce32bd83b97
4729e20b-1b03-8e14-87e9-5ce32bd83b97
cdd1e30b-1b03-8e14-87e9-5ce32bd83b97
8442e40b-1b03-8e14-87e9-5ce32bd83b97
9496e50b-1b03-8e14-87e9-5ce32bd83b97

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

An 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

An UUIDv3 is made out of a MD5 hash and an 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: