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)

019cd517-62fd-7063-9216-c8435abb7a47
019cd517-62fe-7200-bf35-ad89bfac30d6
019cd517-62fe-7340-be8b-05626ff6e189
019cd517-62fe-745f-bf28-dec31cd07351
019cd517-62fe-7579-8191-b7a14137a6ef
019cd517-62fe-7694-bc9e-899eeb2242f5
019cd517-62fe-77af-8286-b8705f7e9fe8
019cd517-62fe-78c9-a4e9-1593be65adc1
019cd517-62fe-79e4-b541-176698970e20
019cd517-62fe-7afa-8d47-6658283bd3ba
019cd517-62fe-7c11-8bd1-51f6d3f2a243
019cd517-62fe-7d2c-9869-261487f7a19e
019cd517-62fe-7e1d-ba95-8c456d5c5680
019cd517-62fe-7f3c-9df9-0db5f5f6ea05
019cd517-62ff-7057-9dbe-2b22e0bfee6b

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)

1f11c15f-50c4-6dbe-84e5-4cf95d479851
1f11c15f-50c4-6f6c-84e5-4cf95d479851
1f11c15f-50c5-6052-84e5-4cf95d479851
1f11c15f-50c5-6124-84e5-4cf95d479851
1f11c15f-50c5-6200-84e5-4cf95d479851
1f11c15f-50c5-62c8-84e5-4cf95d479851
1f11c15f-50c5-639a-84e5-4cf95d479851
1f11c15f-50c5-6462-84e5-4cf95d479851
1f11c15f-50c5-652a-84e5-4cf95d479851
1f11c15f-50c5-65fc-84e5-4cf95d479851
1f11c15f-50c5-6732-84e5-4cf95d479851
1f11c15f-50c5-6804-84e5-4cf95d479851
1f11c15f-50c5-68cc-84e5-4cf95d479851
1f11c15f-50c5-6994-84e5-4cf95d479851
1f11c15f-50c5-6a5c-84e5-4cf95d479851

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)

a721b6ad-af10-49e4-ad9f-4ada83ca6e73
2c16c516-0770-446c-862a-36851d53f559
d0f62cab-59fe-41de-a0d5-edbb5a738381
43149d10-b30c-4fc0-87fc-a4e2ba637486
5d2ef1e9-1bc4-4f44-ac2d-439cce8628ea
ef15ee7b-bd23-4a6a-b373-31a9f240500e
9bd59317-716a-4c37-8858-6f6fcb632b50
7215c726-b335-4e17-bfed-5c561b8bbe4f
e30e9a46-7ab9-4316-9474-58e3e3b16cdc
beeaa364-2ec6-4321-a301-4f2bbe65c6f1
a96ccc4c-97e7-453b-8a60-6139c6f9b4f1
af0d5f79-b580-4f6f-9594-3c71eb1fc949
d3923caa-ff75-46f1-93c2-8c1e97f0287a
483577cf-fd40-4abc-b355-7ec6c54cf4cd
b7555ee7-dde8-4d39-99dc-de397688b3e7

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)

f50c5f7a-1c15-11f1-84e5-4cf95d479851
f50c5fde-1c15-11f1-84e5-4cf95d479851
f50c6042-1c15-11f1-84e5-4cf95d479851
f50c60a6-1c15-11f1-84e5-4cf95d479851
f50c6100-1c15-11f1-84e5-4cf95d479851
f50c6164-1c15-11f1-84e5-4cf95d479851
f50c61be-1c15-11f1-84e5-4cf95d479851
f50c6222-1c15-11f1-84e5-4cf95d479851
f50c6286-1c15-11f1-84e5-4cf95d479851
f50c62ea-1c15-11f1-84e5-4cf95d479851
f50c634e-1c15-11f1-84e5-4cf95d479851
f50c63a8-1c15-11f1-84e5-4cf95d479851
f50c640c-1c15-11f1-84e5-4cf95d479851
f50c6470-1c15-11f1-84e5-4cf95d479851
f50c64d4-1c15-11f1-84e5-4cf95d479851

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)

33e0a119-0e00-8504-87ea-5ce32bd83b97
64d0a219-0e00-8504-87ea-5ce32bd83b97
ce90a319-0e00-8504-87ea-5ce32bd83b97
0652a419-0e00-8504-87ea-5ce32bd83b97
c415a519-0e00-8504-87ea-5ce32bd83b97
592aa619-0e00-8504-87ea-5ce32bd83b97
d7e3a719-0e00-8504-87ea-5ce32bd83b97
383ea819-0e00-8504-87ea-5ce32bd83b97
3e83a919-0e00-8504-87ea-5ce32bd83b97
a7b3ab19-0e00-8504-87ea-5ce32bd83b97
a603ac19-0e00-8504-87ea-5ce32bd83b97
8bb2ad19-0e00-8504-87ea-5ce32bd83b97
ff2eae19-0e00-8504-87ea-5ce32bd83b97
f480af19-0e00-8504-87ea-5ce32bd83b97
e4acb019-0e00-8504-87ea-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: