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)

0193e926-6b33-7954-b173-022522933171
0193e926-6b33-7af6-a9c1-49712e2b3f20
0193e926-6b33-7c3a-8777-7c3c592277ac
0193e926-6b33-7d5d-a789-dd3b48c75788
0193e926-6b33-7e73-9bbd-8a7f64fece9c
0193e926-6b33-7f8e-a152-61e96da571a8
0193e926-6b34-70a8-ad5f-3f2f1cf461f7
0193e926-6b34-71d3-8cc1-e9b515437c70
0193e926-6b34-72ea-bf86-b243c8dc805d
0193e926-6b34-7405-96c3-1bd1f11afb50
0193e926-6b34-751b-b535-ebee34dd888f
0193e926-6b34-7632-8d1d-6b23f0adb929
0193e926-6b34-7748-ba6d-eb658d3e1fa9
0193e926-6b34-785f-b973-c12d5d7a7c98
0193e926-6b34-7979-befb-d12e4c5ea4c8

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)

1efbf958-03cf-6c00-a9ba-4cf95d479851
1efbf958-03cf-6d86-a9ba-4cf95d479851
1efbf958-03cf-6e6c-a9ba-4cf95d479851
1efbf958-03cf-6f34-a9ba-4cf95d479851
1efbf958-03cf-6ff2-a9ba-4cf95d479851
1efbf958-03d0-60ba-a9ba-4cf95d479851
1efbf958-03d0-6178-a9ba-4cf95d479851
1efbf958-03d0-6236-a9ba-4cf95d479851
1efbf958-03d0-62f4-a9ba-4cf95d479851
1efbf958-03d0-63b2-a9ba-4cf95d479851
1efbf958-03d0-64f2-a9ba-4cf95d479851
1efbf958-03d0-65ba-a9ba-4cf95d479851
1efbf958-03d0-6682-a9ba-4cf95d479851
1efbf958-03d0-6740-a9ba-4cf95d479851
1efbf958-03d0-67f4-a9ba-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)

1477c906-f5be-477d-a18c-7ad9ab1588fb
8381fcbf-92b3-4eb5-bff9-a7645a49b282
588821a6-db21-460b-9be1-a888bdd1e900
7631ae4e-3364-486c-b384-411529ff5174
4932586c-545c-4448-a898-d2bab0568497
c50bcc1b-2f86-4386-86d4-0a044da19558
1d16444e-1f6d-4e39-8597-094f6bcd528e
6abfeb7c-f04f-4b08-8283-5303c1c286d2
0495b36f-f8bf-4fec-9ce6-ab56d1131ea8
1e949788-66c7-422a-9ad0-4417fdf6f784
4d8578c0-ca9d-459b-ad64-1e5e89abc275
3bfb2186-cd85-46a3-ae80-543cd0c35e6b
eccfb070-695f-4014-af13-eff5d9b081b7
8d3383a6-a0e6-4164-85b7-0ca8ca343668
0b68f02c-c2d0-4040-a1e3-e0f66b0a8327

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)

803d0d08-bf95-11ef-a9ba-4cf95d479851
803d0d6c-bf95-11ef-a9ba-4cf95d479851
803d0dc6-bf95-11ef-a9ba-4cf95d479851
803d0e2a-bf95-11ef-a9ba-4cf95d479851
803d0e84-bf95-11ef-a9ba-4cf95d479851
803d0ede-bf95-11ef-a9ba-4cf95d479851
803d0f42-bf95-11ef-a9ba-4cf95d479851
803d0f9c-bf95-11ef-a9ba-4cf95d479851
803d100a-bf95-11ef-a9ba-4cf95d479851
803d1064-bf95-11ef-a9ba-4cf95d479851
803d10c8-bf95-11ef-a9ba-4cf95d479851
803d112c-bf95-11ef-a9ba-4cf95d479851
803d1190-bf95-11ef-a9ba-4cf95d479851
803d11f4-bf95-11ef-a9ba-4cf95d479851
803d1258-bf95-11ef-a9ba-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 2: Resolution of 1 milliseconds, random part of 16 bits, UTC time, 48 bit random "signature", UUIDv8 conform:
- 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)
-  4 bit UUID version 8
- 12 bit UTC Day of the year (1..366, hex encoded)
-  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 conform:
- 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)

b8eb6e09-02e2-8164-87e8-5ce32bd83b96
234b6f09-02e2-8164-87e8-5ce32bd83b96
eaca7009-02e2-8164-87e8-5ce32bd83b96
ca027109-02e2-8164-87e8-5ce32bd83b96
0b7b7209-02e2-8164-87e8-5ce32bd83b96
5bb67309-02e2-8164-87e8-5ce32bd83b96
a67f7409-02e2-8164-87e8-5ce32bd83b96
7e657509-02e2-8164-87e8-5ce32bd83b96
2ea27609-02e2-8164-87e8-5ce32bd83b96
884f7709-02e2-8164-87e8-5ce32bd83b96
a3e07809-02e2-8164-87e8-5ce32bd83b96
569c7909-02e2-8164-87e8-5ce32bd83b96
59777a09-02e2-8164-87e8-5ce32bd83b96
1d4c7b09-02e2-8164-87e8-5ce32bd83b96
57d87c09-02e2-8164-87e8-5ce32bd83b96

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: