UUID & MAC Utils by Daniel Marschall

View the source code

Overview

• Generate time-based UUIDs
  • New: Generate Unix Epoch time-based (version 7) UUID
  • New: Generate reordered Gregorian time-based (version 6) UUID
  • Generate Gregorian time-based (version 1) UUID
  • New: Generate SQL Server sortable time-based (version 8) UUID
• Generate random UUIDs
  • Generate random (version 4) 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)

019fdd9f-dfe7-75dc-8ff2-8027a3c526dc
019fdd9f-dfe7-7779-9d1e-22a8b84ab7ef
019fdd9f-dfe7-78b5-96f5-e7233d3f833a
019fdd9f-dfe7-79cf-a92a-120026a04ad4
019fdd9f-dfe7-7ae2-a21a-8f0b253c5a21
019fdd9f-dfe7-7bf8-94ad-9c2b2214ecec
019fdd9f-dfe7-7d0b-b97a-576ec7d62b60
019fdd9f-dfe7-7e25-9762-f378c4e5deae
019fdd9f-dfe7-7f40-9c58-3cf243605bc3
019fdd9f-dfe8-7052-a382-55fb0f331818
019fdd9f-dfe8-7169-a32c-f59264b6ab0f
019fdd9f-dfe8-727b-b094-399dd1ca4529
019fdd9f-dfe8-738e-8157-c62231132e2c
019fdd9f-dfe8-74a0-8ea3-2505181577cf
019fdd9f-dfe8-75b7-bacc-ba425c3b1b03

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)

1f192934-89ba-69cc-a187-4cf95d479851
1f192934-89ba-6b70-a187-4cf95d479851
1f192934-89ba-6c60-a187-4cf95d479851
1f192934-89ba-6d28-a187-4cf95d479851
1f192934-89ba-6df0-a187-4cf95d479851
1f192934-89ba-6eb8-a187-4cf95d479851
1f192934-89ba-6f8a-a187-4cf95d479851
1f192934-89bb-6052-a187-4cf95d479851
1f192934-89bb-6110-a187-4cf95d479851
1f192934-89bb-61d8-a187-4cf95d479851
1f192934-89bb-6318-a187-4cf95d479851
1f192934-89bb-63f4-a187-4cf95d479851
1f192934-89bb-64b2-a187-4cf95d479851
1f192934-89bb-6570-a187-4cf95d479851
1f192934-89bb-662e-a187-4cf95d479851

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)

489bb700-9293-11f1-a187-4cf95d479851
489bb764-9293-11f1-a187-4cf95d479851
489bb7c8-9293-11f1-a187-4cf95d479851
489bb82c-9293-11f1-a187-4cf95d479851
489bb886-9293-11f1-a187-4cf95d479851
489bb8e0-9293-11f1-a187-4cf95d479851
489bb944-9293-11f1-a187-4cf95d479851
489bb9a8-9293-11f1-a187-4cf95d479851
489bba0c-9293-11f1-a187-4cf95d479851
489bba66-9293-11f1-a187-4cf95d479851
489bbad4-9293-11f1-a187-4cf95d479851
489bbb38-9293-11f1-a187-4cf95d479851
489bbb92-9293-11f1-a187-4cf95d479851
489bbbec-9293-11f1-a187-4cf95d479851
489bbc46-9293-11f1-a187-4cf95d479851

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, whereas 8 is the version)
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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, whereas 8 is the version) = WRONG!!!
-  2 bit UUID Variant (0b10)
-  2 bit Unused (must be zero)
- 12 bit UTC Year (hex encoded) BIG ENDIAN
- 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)

7a211f32-7c04-8b0d-87ea-5ce32bd83b97
15b32032-7c04-8b0d-87ea-5ce32bd83b97
b1982132-7c04-8b0d-87ea-5ce32bd83b97
c8f92232-7c04-8b0d-87ea-5ce32bd83b97
b8b42332-7c04-8b0d-87ea-5ce32bd83b97
5fd62432-7c04-8b0d-87ea-5ce32bd83b97
406b2532-7c04-8b0d-87ea-5ce32bd83b97
6c642632-7c04-8b0d-87ea-5ce32bd83b97
0b642732-7c04-8b0d-87ea-5ce32bd83b97
2d7a2832-7c04-8b0d-87ea-5ce32bd83b97
57212932-7c04-8b0d-87ea-5ce32bd83b97
196b2a32-7c04-8b0d-87ea-5ce32bd83b97
1ae22b32-7c04-8b0d-87ea-5ce32bd83b97
5bfb2c32-7c04-8b0d-87ea-5ce32bd83b97
b5992d32-7c04-8b0d-87ea-5ce32bd83b97

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)

a7e7144b-99c4-4f18-9842-98b951142a2d
5aeaec56-d42f-480c-8105-0335a47098fa
ac17bf5a-bfbd-4df6-85ce-c377cef21c3e
5cd907bc-51e4-4f51-9357-f35ab4f75a7a
7d55214c-b1c8-4bce-9aca-77cfe4d2b59e
2084c09e-4446-45ce-8a53-e1056e85c25f
d0cdef70-96d4-4bb3-b135-c8c69c17c310
7548c308-8e63-4297-8ea4-294adecb2f0d
930b8ddd-3860-489a-a34f-2a37da633db8
4d819e19-aa99-4175-a268-262ea0215d0e
3f6b3476-f639-436f-91fe-315eaeb2b0ea
8481c9a7-57b6-4cdb-be85-e7ca6e7d6c6b
7d4c6d61-6451-4f9b-ada3-128a281ca1d3
75a171bf-6fd8-46b4-b55f-34db9251e8a1
8782d8f0-3345-40a6-bff1-ca1c7ce6f965

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: