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)

019ef48e-ef65-7c8c-8797-07a3290da8ea
019ef48e-ef65-7e09-9c10-e1c1bc17c6fb
019ef48e-ef65-7f40-870f-968b16169d60
019ef48e-ef66-705b-b5ed-74acd4a56622
019ef48e-ef66-7171-a9a0-30c7786d0256
019ef48e-ef66-7288-9a05-eb6ee5e29525
019ef48e-ef66-739e-b980-d30eef0b808e
019ef48e-ef66-74b1-b0d0-ba9c76a3fbd6
019ef48e-ef66-75c7-9f79-0729580a74a8
019ef48e-ef66-76da-b932-8c6102929eda
019ef48e-ef66-77e8-a898-9ef570f03888
019ef48e-ef66-790b-b411-b6d3aa2ae312
019ef48e-ef66-7a1d-a582-bda4feab69d1
019ef48e-ef66-7b30-b7cc-7435146a13fc
019ef48e-ef66-7c46-94f4-b38c6d7287e3

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)

1f16f032-2e8e-6234-bc11-4cf95d479851
1f16f032-2e8e-63ce-bc11-4cf95d479851
1f16f032-2e8e-64be-bc11-4cf95d479851
1f16f032-2e8e-6590-bc11-4cf95d479851
1f16f032-2e8e-6658-bc11-4cf95d479851
1f16f032-2e8e-6720-bc11-4cf95d479851
1f16f032-2e8e-67e8-bc11-4cf95d479851
1f16f032-2e8e-68b0-bc11-4cf95d479851
1f16f032-2e8e-696e-bc11-4cf95d479851
1f16f032-2e8e-6a36-bc11-4cf95d479851
1f16f032-2e8e-6b8a-bc11-4cf95d479851
1f16f032-2e8e-6c5c-bc11-4cf95d479851
1f16f032-2e8e-6d24-bc11-4cf95d479851
1f16f032-2e8e-6de2-bc11-4cf95d479851
1f16f032-2e8e-6eaa-bc11-4cf95d479851

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)

22e8ef7c-6f03-11f1-bc11-4cf95d479851
22e8efea-6f03-11f1-bc11-4cf95d479851
22e8f058-6f03-11f1-bc11-4cf95d479851
22e8f0d0-6f03-11f1-bc11-4cf95d479851
22e8f134-6f03-11f1-bc11-4cf95d479851
22e8f1ac-6f03-11f1-bc11-4cf95d479851
22e8f21a-6f03-11f1-bc11-4cf95d479851
22e8f27e-6f03-11f1-bc11-4cf95d479851
22e8f2ec-6f03-11f1-bc11-4cf95d479851
22e8f35a-6f03-11f1-bc11-4cf95d479851
22e8f3be-6f03-11f1-bc11-4cf95d479851
22e8f422-6f03-11f1-bc11-4cf95d479851
22e8f490-6f03-11f1-bc11-4cf95d479851
22e8f4ea-6f03-11f1-bc11-4cf95d479851
22e8f562-6f03-11f1-bc11-4cf95d479851

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)

fe6da530-0a03-8e0a-87ea-5ce32bd83b97
94c6a630-0a03-8e0a-87ea-5ce32bd83b97
0855a730-0a03-8e0a-87ea-5ce32bd83b97
3e60a830-0a03-8e0a-87ea-5ce32bd83b97
cafba930-0a03-8e0a-87ea-5ce32bd83b97
73b8aa30-0a03-8e0a-87ea-5ce32bd83b97
9f41ab30-0a03-8e0a-87ea-5ce32bd83b97
2253ac30-0a03-8e0a-87ea-5ce32bd83b97
7ee0ae30-0a03-8e0a-87ea-5ce32bd83b97
997faf30-0a03-8e0a-87ea-5ce32bd83b97
986bb030-0a03-8e0a-87ea-5ce32bd83b97
fe04b130-0a03-8e0a-87ea-5ce32bd83b97
d445b230-0a03-8e0a-87ea-5ce32bd83b97
5650b330-0a03-8e0a-87ea-5ce32bd83b97
2ce3b430-0a03-8e0a-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)

8e0758bc-5557-43c9-b0f6-85e7fcd69259
71fadcae-42bc-4e98-9112-4e687fb4d6ff
4ab85b24-a70d-40c8-97c2-fe941b34b6b8
a97c6d37-a113-43f0-9d55-46b29b76e5d4
45f2b5b3-1eba-40b7-bbb9-7cabd347ff8b
69b24ce4-f5c4-46d0-b311-b992d88e0efd
8f92e2fb-19ca-4920-941f-d1c17ebb67a1
03317309-e4a4-482a-93a1-e40abb0b5eb8
1fda072d-1e03-425d-8037-4838b15911f2
3c0c170f-db3e-4046-abe8-48a4e97dec45
a13725d9-41b7-443e-9c24-945bd9f20c0c
4e0d9ec4-7f3f-466e-8097-1489839ee177
5780eb59-40f9-4819-82ed-0b4e404c933c
2240d06e-c209-421b-baa3-21dfb7cc0b6a
f2ac81c4-1902-4baf-9deb-e4d9b0cc76c0

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: