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)

019c016c-ea4e-7bd3-9de1-44d557f53670
019c016c-ea4e-7d82-ad02-e60e68378fb4
019c016c-ea4e-7ec5-8907-41f31c8fb37f
019c016c-ea4e-7ff0-b94c-f07412374034
019c016c-ea4f-710f-b89e-be96f00123e2
019c016c-ea4f-7242-8d00-4b75e887060f
019c016c-ea4f-736d-9fb3-987be130f3b1
019c016c-ea4f-7494-b4c5-4202923de75c
019c016c-ea4f-75b3-8ac0-4a288e37a613
019c016c-ea4f-76cd-95c2-85474aa2a071
019c016c-ea4f-77e8-81a7-2ec45de94dd5
019c016c-ea4f-7907-8cf3-67b9be664b5a
019c016c-ea4f-7a25-8f8d-8a034e0b9856
019c016c-ea4f-7b44-a124-e48070911351
019c016c-ea4f-7c63-9877-1ad1e8b3a8aa

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)

1f0fbc9c-2021-600a-a344-4cf95d479851
1f0fbc9c-2021-61a4-a344-4cf95d479851
1f0fbc9c-2021-628a-a344-4cf95d479851
1f0fbc9c-2021-635c-a344-4cf95d479851
1f0fbc9c-2021-641a-a344-4cf95d479851
1f0fbc9c-2021-64e2-a344-4cf95d479851
1f0fbc9c-2021-65a0-a344-4cf95d479851
1f0fbc9c-2021-6668-a344-4cf95d479851
1f0fbc9c-2021-6726-a344-4cf95d479851
1f0fbc9c-2021-67e4-a344-4cf95d479851
1f0fbc9c-2021-692e-a344-4cf95d479851
1f0fbc9c-2021-69f6-a344-4cf95d479851
1f0fbc9c-2021-6ab4-a344-4cf95d479851
1f0fbc9c-2021-6b72-a344-4cf95d479851
1f0fbc9c-2021-6c30-a344-4cf95d479851

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)

99a414a1-97e0-432f-b5be-f126cc51616b
2404d2a1-3657-4e35-9d84-37c53a6aba65
90bb4b8b-b27e-4823-92d3-abd95970510d
ae29dd00-4cd5-4459-9c40-05f2cbb25546
27b51d60-74ad-4324-a559-43866f61e115
156d527a-2430-4e1f-9851-742368c78e47
cede7127-ee5b-4314-bd35-7a0374d20f4a
5c5cd52a-73a4-4a3d-960a-d9f0d7094572
91291319-98a3-4b18-a8fc-1f729d2d590f
cac82e3b-e3ee-452b-b29e-c75c391606cc
354ae725-3e47-4c59-becf-92d31b5cc560
bf4387a2-80be-4085-9f28-94797f4a5453
7b51a16d-9675-43ba-9014-e280049d1b76
2b96ad95-8371-4cad-9127-b885147d3422
057508c6-7428-4df0-a5d9-a91139aadf86

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)

c202214e-fbc9-11f0-a344-4cf95d479851
c20221b2-fbc9-11f0-a344-4cf95d479851
c2022216-fbc9-11f0-a344-4cf95d479851
c2022284-fbc9-11f0-a344-4cf95d479851
c20222de-fbc9-11f0-a344-4cf95d479851
c202234c-fbc9-11f0-a344-4cf95d479851
c20223b0-fbc9-11f0-a344-4cf95d479851
c2022414-fbc9-11f0-a344-4cf95d479851
c2022478-fbc9-11f0-a344-4cf95d479851
c20224dc-fbc9-11f0-a344-4cf95d479851
c2022540-fbc9-11f0-a344-4cf95d479851
c20225a4-fbc9-11f0-a344-4cf95d479851
c2022608-fbc9-11f0-a344-4cf95d479851
c2022676-fbc9-11f0-a344-4cf95d479851
c20226d0-fbc9-11f0-a344-4cf95d479851

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)

5f440a15-1c05-8b01-87ea-5ce32bd83b97
3b7d0b15-1c05-8b01-87ea-5ce32bd83b97
f6fc0c15-1c05-8b01-87ea-5ce32bd83b97
95330d15-1c05-8b01-87ea-5ce32bd83b97
df600e15-1c05-8b01-87ea-5ce32bd83b97
aba50f15-1c05-8b01-87ea-5ce32bd83b97
46651015-1c05-8b01-87ea-5ce32bd83b97
a0621215-1c05-8b01-87ea-5ce32bd83b97
63f31315-1c05-8b01-87ea-5ce32bd83b97
70691415-1c05-8b01-87ea-5ce32bd83b97
22061515-1c05-8b01-87ea-5ce32bd83b97
c2231615-1c05-8b01-87ea-5ce32bd83b97
1cca1715-1c05-8b01-87ea-5ce32bd83b97
7e2c1815-1c05-8b01-87ea-5ce32bd83b97
7ac51915-1c05-8b01-87ea-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: