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)

01a09f5f-91f5-75a6-b432-27669a37fe4e
01a09f5f-91f5-7761-926b-43244dca4831
01a09f5f-91f5-78a0-9911-4c2682bb9dea
01a09f5f-91f5-79b7-9316-d66525424bb9
01a09f5f-91f5-7acd-bbc5-4d304bca8fa0
01a09f5f-91f5-7be4-ab43-43cb5b208d37
01a09f5f-91f5-7d07-aa68-d875621222f7
01a09f5f-91f5-7e1d-aa9a-b69732495d88
01a09f5f-91f5-7f30-97b1-160866ca89fe
01a09f5f-91f6-7046-926a-a28a87837823
01a09f5f-91f6-7159-91b7-4be199d583a1
01a09f5f-91f6-726b-a7a1-9dcd6bb51e92
01a09f5f-91f6-737d-8b70-1d30dba2cb27
01a09f5f-91f6-7490-baf1-9035a4bc0074
01a09f5f-91f6-75a6-b120-610d5897ad6a

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)

1f1b0239-8b6e-6b58-b410-4cf95d479851
1f1b0239-8b6e-6d24-b410-4cf95d479851
1f1b0239-8b6e-6e0a-b410-4cf95d479851
1f1b0239-8b6e-6ed2-b410-4cf95d479851
1f1b0239-8b6e-6f90-b410-4cf95d479851
1f1b0239-8b6f-604e-b410-4cf95d479851
1f1b0239-8b6f-610c-b410-4cf95d479851
1f1b0239-8b6f-61ca-b410-4cf95d479851
1f1b0239-8b6f-627e-b410-4cf95d479851
1f1b0239-8b6f-633c-b410-4cf95d479851
1f1b0239-8b6f-649a-b410-4cf95d479851
1f1b0239-8b6f-656c-b410-4cf95d479851
1f1b0239-8b6f-662a-b410-4cf95d479851
1f1b0239-8b6f-66fc-b410-4cf95d479851
1f1b0239-8b6f-67ba-b410-4cf95d479851

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)

98b6f88c-b023-11f1-b410-4cf95d479851
98b6f8f0-b023-11f1-b410-4cf95d479851
98b6f954-b023-11f1-b410-4cf95d479851
98b6f9ae-b023-11f1-b410-4cf95d479851
98b6fa1c-b023-11f1-b410-4cf95d479851
98b6fa80-b023-11f1-b410-4cf95d479851
98b6fada-b023-11f1-b410-4cf95d479851
98b6fb34-b023-11f1-b410-4cf95d479851
98b6fb98-b023-11f1-b410-4cf95d479851
98b6fbfc-b023-11f1-b410-4cf95d479851
98b6fc60-b023-11f1-b410-4cf95d479851
98b6fcc4-b023-11f1-b410-4cf95d479851
98b6fd1e-b023-11f1-b410-4cf95d479851
98b6fd82-b023-11f1-b410-4cf95d479851
98b6fddc-b023-11f1-b410-4cf95d479851

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)

ecb4c437-5c02-8110-87ea-5ce32bd83b97
42f5c537-5c02-8110-87ea-5ce32bd83b97
616ac637-5c02-8110-87ea-5ce32bd83b97
0363c737-5c02-8110-87ea-5ce32bd83b97
5aecc837-5c02-8110-87ea-5ce32bd83b97
6539c937-5c02-8110-87ea-5ce32bd83b97
1e37ca37-5c02-8110-87ea-5ce32bd83b97
e609cb37-5c02-8110-87ea-5ce32bd83b97
b818cc37-5c02-8110-87ea-5ce32bd83b97
dd60cd37-5c02-8110-87ea-5ce32bd83b97
32e1ce37-5c02-8110-87ea-5ce32bd83b97
d459cf37-5c02-8110-87ea-5ce32bd83b97
adedd037-5c02-8110-87ea-5ce32bd83b97
bf2fd137-5c02-8110-87ea-5ce32bd83b97
4a8ad237-5c02-8110-87ea-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)

acbecdfd-d85f-4eec-bb4e-8cc49ee9ada9
827bbb40-5d39-4310-8716-780762cb9de4
e7c75f2b-a9d3-4de8-ae60-26741de06e12
e170c79e-197d-4562-8754-b80c3affd09f
3e23d49f-c98f-4869-8110-4fd451f454c0
b254b1de-cc8f-41f3-bde6-b9bbaf598d98
8dbc7acc-cc49-4732-9fe8-9778665c0684
6c2825a9-7ee4-4f18-9177-507d6c76405d
c5323982-3a02-4d3a-bfd0-74371302b21f
de353a30-9af4-4ed0-ba06-456f8de8c1cb
3ba7ecec-459b-4d47-8f81-0ad696a3c9e1
ec8f8902-02ef-48b6-a13c-9504d6071c2d
8dbbe536-23e5-426d-9f6c-d11cf6550a26
0615c7fc-8acd-4b1f-b3c3-2c5e1e7ac31e
acc597e9-1f17-4471-a3c4-16050138a7f8

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: