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)

019b1f4f-8e2f-77c7-bb21-59830505ee0c
019b1f4f-8e2f-795d-9cc0-c9520472f834
019b1f4f-8e2f-7a98-9c9c-014460381673
019b1f4f-8e2f-7bbb-bf2e-e773d1cf6514
019b1f4f-8e2f-7cda-8cdd-a7c9219705df
019b1f4f-8e2f-7df4-945d-3b682cafa5b1
019b1f4f-8e2f-7f0b-930b-5e72c776e70d
019b1f4f-8e30-7025-879f-365dc8153ca2
019b1f4f-8e30-7140-be9a-f777ce8b83bd
019b1f4f-8e30-725b-a316-7c0a81508a8b
019b1f4f-8e30-7375-b1d3-d43c45b8d21d
019b1f4f-8e30-7490-bc64-3a43b45f0190
019b1f4f-8e30-75aa-bbb3-be517e86786f
019b1f4f-8e30-76c1-bab6-f12267265016
019b1f4f-8e30-77e0-bcd1-cdb7fb3c42ca

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)

1f0d9492-7238-6a16-ab26-4cf95d479851
1f0d9492-7238-6bba-ab26-4cf95d479851
1f0d9492-7238-6ca0-ab26-4cf95d479851
1f0d9492-7238-6d72-ab26-4cf95d479851
1f0d9492-7238-6e44-ab26-4cf95d479851
1f0d9492-7238-6f0c-ab26-4cf95d479851
1f0d9492-7238-6fca-ab26-4cf95d479851
1f0d9492-7239-6092-ab26-4cf95d479851
1f0d9492-7239-6150-ab26-4cf95d479851
1f0d9492-7239-620e-ab26-4cf95d479851
1f0d9492-7239-634e-ab26-4cf95d479851
1f0d9492-7239-6416-ab26-4cf95d479851
1f0d9492-7239-64de-ab26-4cf95d479851
1f0d9492-7239-65a6-ab26-4cf95d479851
1f0d9492-7239-666e-ab26-4cf95d479851

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)

68687430-1896-4a35-996f-83569f5a0d63
036223ef-32ae-4a09-a0e1-bfd0839a4592
5a7659d5-b72e-45f8-ad56-93a0d0faaa7f
9a646a27-a6e8-4f18-99be-2a70af2c99a0
b9b98fba-3e52-4806-a54a-6f31829ddf01
2af42603-3f57-4144-8d4a-7c1bb605d174
bea20ebf-c671-4e09-89b9-26bbdd3553c4
ddfe7304-eb6e-4cbd-b4e8-c9e193728129
0adde1b7-4697-4985-b261-8c53f9d7c25b
d2fded72-42e3-43ce-b3be-524c647311ba
4392248d-0dfd-4fd8-b4af-b79af6eb55cb
848fca66-b561-4cf6-a50f-5b3da0aac664
8440d6ce-cace-4468-9bd1-8c8b5e6b52a7
6b683cd9-564d-4ad1-aa4c-22dc3a3499b1
7b9c05c2-f2ff-47c2-85a5-bb39559aa3bf

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)

27239ba0-d949-11f0-ab26-4cf95d479851
27239c0e-d949-11f0-ab26-4cf95d479851
27239c7c-d949-11f0-ab26-4cf95d479851
27239ce0-d949-11f0-ab26-4cf95d479851
27239d44-d949-11f0-ab26-4cf95d479851
27239d9e-d949-11f0-ab26-4cf95d479851
27239e0c-d949-11f0-ab26-4cf95d479851
27239e66-d949-11f0-ab26-4cf95d479851
27239eca-d949-11f0-ab26-4cf95d479851
27239f38-d949-11f0-ab26-4cf95d479851
27239f9c-d949-11f0-ab26-4cf95d479851
2723a000-d949-11f0-ab26-4cf95d479851
2723a06e-d949-11f0-ab26-4cf95d479851
2723a0d2-d949-11f0-ab26-4cf95d479851
2723a136-d949-11f0-ab26-4cf95d479851

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)

2c291906-0200-8d15-87e9-5ce32bd83b97
5f981a06-0200-8d15-87e9-5ce32bd83b97
4e3c1b06-0200-8d15-87e9-5ce32bd83b97
e0e01c06-0200-8d15-87e9-5ce32bd83b97
1e881d06-0200-8d15-87e9-5ce32bd83b97
f97d1e06-0200-8d15-87e9-5ce32bd83b97
a6a21f06-0200-8d15-87e9-5ce32bd83b97
23f12006-0200-8d15-87e9-5ce32bd83b97
b2e22106-0200-8d15-87e9-5ce32bd83b97
eba92206-0200-8d15-87e9-5ce32bd83b97
7cda2306-0200-8d15-87e9-5ce32bd83b97
67ee2406-0200-8d15-87e9-5ce32bd83b97
5a6b2506-0200-8d15-87e9-5ce32bd83b97
77c52606-0200-8d15-87e9-5ce32bd83b97
e9c12706-0200-8d15-87e9-5ce32bd83b97

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: