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)

019c5933-ed44-7284-92d8-43a6475440d7
019c5933-ed44-7429-8d2b-3540f0a2ee7a
019c5933-ed44-7569-b1a3-4d352a093e29
019c5933-ed44-7684-8ab9-5abde51733be
019c5933-ed44-7796-ad7e-efe1d2cca1a3
019c5933-ed44-78ad-a8f2-e41e58721c98
019c5933-ed44-79c3-bfe4-cbd5b256f5e3
019c5933-ed44-7ada-a6ac-404e2211bf0e
019c5933-ed44-7bec-8a19-7d7632d5e651
019c5933-ed44-7d03-ae36-443bb40a7063
019c5933-ed44-7e15-9a5f-ef6bae211cb1
019c5933-ed44-7f2c-8b0a-f40f504261b4
019c5933-ed45-704a-9ce5-bfdf8422aa82
019c5933-ed45-7161-a749-c3f39118a33c
019c5933-ed45-7277-bbfc-a736bddb6cda

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)

1f1092e8-fe5a-6204-b520-4cf95d479851
1f1092e8-fe5a-63b2-b520-4cf95d479851
1f1092e8-fe5a-648e-b520-4cf95d479851
1f1092e8-fe5a-6560-b520-4cf95d479851
1f1092e8-fe5a-661e-b520-4cf95d479851
1f1092e8-fe5a-66dc-b520-4cf95d479851
1f1092e8-fe5a-679a-b520-4cf95d479851
1f1092e8-fe5a-684e-b520-4cf95d479851
1f1092e8-fe5a-690c-b520-4cf95d479851
1f1092e8-fe5a-69c0-b520-4cf95d479851
1f1092e8-fe5a-6b32-b520-4cf95d479851
1f1092e8-fe5a-6bfa-b520-4cf95d479851
1f1092e8-fe5a-6cb8-b520-4cf95d479851
1f1092e8-fe5a-6d6c-b520-4cf95d479851
1f1092e8-fe5a-6e20-b520-4cf95d479851

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)

dc95c29e-f3ab-4d7f-b16a-390c1366ab6a
34a35f16-ad6a-4647-bc4a-82413fa8a0a4
53913608-40ec-43b7-9a42-126eaaaa98bb
43b5bdc7-d6b5-4999-99e1-a22a937c73fa
3be8ad28-ab64-4a97-9cbb-d730ede6c442
92a68dc1-e9ca-4b6a-bea4-0ce6a7833523
27a03c50-c54e-48cb-b549-34ab1f102027
cd2eddbc-ca1c-44e9-a5ba-f83561af1120
529b7baa-ae2a-4ae3-b2c4-108cf2f3ab6f
f6c62d27-d9b3-4e51-900f-66aaabf6a481
0d92b145-ac0f-4881-bbe5-8460229b8f6c
c40feab6-d810-4bec-8089-43618dc05a44
2178fb61-0b31-441e-9162-838659c92506
1125b6e7-48b7-4ced-af09-1d2e2c9b8341
b6b9d97e-1e23-4118-84eb-8993cb007445

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)

8fe5b334-092e-11f1-b520-4cf95d479851
8fe5b38e-092e-11f1-b520-4cf95d479851
8fe5b3f2-092e-11f1-b520-4cf95d479851
8fe5b456-092e-11f1-b520-4cf95d479851
8fe5b4b0-092e-11f1-b520-4cf95d479851
8fe5b50a-092e-11f1-b520-4cf95d479851
8fe5b56e-092e-11f1-b520-4cf95d479851
8fe5b5c8-092e-11f1-b520-4cf95d479851
8fe5b62c-092e-11f1-b520-4cf95d479851
8fe5b690-092e-11f1-b520-4cf95d479851
8fe5b6f4-092e-11f1-b520-4cf95d479851
8fe5b74e-092e-11f1-b520-4cf95d479851
8fe5b7a8-092e-11f1-b520-4cf95d479851
8fe5b802-092e-11f1-b520-4cf95d479851
8fe5b866-092e-11f1-b520-4cf95d479851

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)

c9da4129-5c05-8c02-87ea-5ce32bd83b97
c9554229-5c05-8c02-87ea-5ce32bd83b97
ba044329-5c05-8c02-87ea-5ce32bd83b97
f0da4429-5c05-8c02-87ea-5ce32bd83b97
2a6a4529-5c05-8c02-87ea-5ce32bd83b97
7e0a4629-5c05-8c02-87ea-5ce32bd83b97
45d94729-5c05-8c02-87ea-5ce32bd83b97
a3114829-5c05-8c02-87ea-5ce32bd83b97
ac994929-5c05-8c02-87ea-5ce32bd83b97
53e64a29-5c05-8c02-87ea-5ce32bd83b97
05d64b29-5c05-8c02-87ea-5ce32bd83b97
4a054c29-5c05-8c02-87ea-5ce32bd83b97
7ecc4d29-5c05-8c02-87ea-5ce32bd83b97
74f94e29-5c05-8c02-87ea-5ce32bd83b97
ae2c4f29-5c05-8c02-87ea-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: