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)

019d8d4b-4647-73c3-a35c-17cc1a77ff1c
019d8d4b-4647-758a-9010-7918cc0c3b1d
019d8d4b-4647-76da-9c63-97fb4027a431
019d8d4b-4647-77f8-bfad-af3acae722b2
019d8d4b-4647-7913-880f-355f82b8f7d9
019d8d4b-4647-7a32-aabc-7b531a99518e
019d8d4b-4647-7b4c-9d25-6c10b69c80b8
019d8d4b-4647-7c67-87e4-802351d06159
019d8d4b-4647-7d82-80fc-f4803671b81c
019d8d4b-4647-7e9c-9263-29c9b8826f56
019d8d4b-4647-7fb7-9b37-22ecab4b52b5
019d8d4b-4648-70d1-94de-1cee608732fc
019d8d4b-4648-71ec-84d9-ba3a52c56160
019d8d4b-4648-7267-aa0f-a85a8b3b9b35
019d8d4b-4648-7386-9157-aeb2e5c70dd8

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)

1f138315-feaa-6a72-9858-4cf95d479851
1f138315-feaa-6c16-9858-4cf95d479851
1f138315-feaa-6cfc-9858-4cf95d479851
1f138315-feaa-6dce-9858-4cf95d479851
1f138315-feaa-6e96-9858-4cf95d479851
1f138315-feaa-6f5e-9858-4cf95d479851
1f138315-feab-6026-9858-4cf95d479851
1f138315-feab-60ee-9858-4cf95d479851
1f138315-feab-61b6-9858-4cf95d479851
1f138315-feab-6274-9858-4cf95d479851
1f138315-feab-63b4-9858-4cf95d479851
1f138315-feab-6486-9858-4cf95d479851
1f138315-feab-6544-9858-4cf95d479851
1f138315-feab-660c-9858-4cf95d479851
1f138315-feab-66d4-9858-4cf95d479851

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)

406012be-21f5-4500-9193-bc786518b363
8a80b904-c15f-4734-8fdd-fc6a99d80623
29581bc8-9fde-49d2-872d-e4effafe3fcf
6b359887-472b-48bb-a7bd-6ddaddc5203e
09eb5ded-5377-46dd-8564-10636c4bf329
b61d39a7-0f18-4032-8a65-ddcad7ce86ed
29971db0-fd8d-487e-8c71-f93ec96504bf
6d8ab4e5-1f1a-4508-a51e-ff9fafb60bb1
d7e1543f-5ffb-43bc-8b34-134add2ccf75
37d33920-c07a-43f0-9072-49c8ca7653f2
65edd650-3312-450b-b0f9-cf6348212d3d
84c911c2-30c1-4f08-a11e-24479bf93f4c
5b2abf2a-eaa2-4b25-9710-231bef7edda7
842b6570-f37c-4e59-bfe3-a6dc2fb4d1ba
90b6fc29-6afa-4c30-8b11-8b0b5375ebcc

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)

5feabbfc-3831-11f1-9858-4cf95d479851
5feabc56-3831-11f1-9858-4cf95d479851
5feabcba-3831-11f1-9858-4cf95d479851
5feabd14-3831-11f1-9858-4cf95d479851
5feabd78-3831-11f1-9858-4cf95d479851
5feabddc-3831-11f1-9858-4cf95d479851
5feabe36-3831-11f1-9858-4cf95d479851
5feabea4-3831-11f1-9858-4cf95d479851
5feabefe-3831-11f1-9858-4cf95d479851
5feabf62-3831-11f1-9858-4cf95d479851
5feabfc6-3831-11f1-9858-4cf95d479851
5feac02a-3831-11f1-9858-4cf95d479851
5feac084-3831-11f1-9858-4cf95d479851
5feac0de-3831-11f1-9858-4cf95d479851
5feac138-3831-11f1-9858-4cf95d479851

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)

3e02e50d-6104-8806-87ea-5ce32bd83b97
b80ce60d-6104-8806-87ea-5ce32bd83b97
f609e70d-6104-8806-87ea-5ce32bd83b97
ad63e80d-6104-8806-87ea-5ce32bd83b97
1081e90d-6104-8806-87ea-5ce32bd83b97
44d6ea0d-6104-8806-87ea-5ce32bd83b97
7cd8eb0d-6104-8806-87ea-5ce32bd83b97
f008ec0d-6104-8806-87ea-5ce32bd83b97
0e73ed0d-6104-8806-87ea-5ce32bd83b97
2b2eee0d-6104-8806-87ea-5ce32bd83b97
a3b2ef0d-6104-8806-87ea-5ce32bd83b97
a0a3f00d-6104-8806-87ea-5ce32bd83b97
9fe1f10d-6104-8806-87ea-5ce32bd83b97
d5e1f20d-6104-8806-87ea-5ce32bd83b97
15a8f40d-6104-8806-87ea-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: