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)

019f2ac3-d1b6-7d71-86ca-e613f2af0723
019f2ac3-d1b6-7f34-987b-dc9ad69812bb
019f2ac3-d1b7-707f-a399-3f9ef655d53e
019f2ac3-d1b7-71a6-8c30-9e4c440a00c9
019f2ac3-d1b7-72c5-8243-b4ff779b802b
019f2ac3-d1b7-73e0-8ec4-b4d04f572ab7
019f2ac3-d1b7-74fe-8fc8-95dc55cba23b
019f2ac3-d1b7-761d-9a54-84e893824ba1
019f2ac3-d1b7-773c-a4ab-d89beacf7f1d
019f2ac3-d1b7-7857-aae0-0aeebd19d720
019f2ac3-d1b7-7971-ab14-021b5f826d34
019f2ac3-d1b7-7a90-bd15-3411fc077a19
019f2ac3-d1b7-7baf-a944-f4c4cfff3d51
019f2ac3-d1b7-7cc9-a2c5-3d93b278dace
019f2ac3-d1b7-7de8-b913-de15596434d9

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)

1f177489-4b16-6290-819d-4cf95d479851
1f177489-4b16-6470-819d-4cf95d479851
1f177489-4b16-656a-819d-4cf95d479851
1f177489-4b16-663c-819d-4cf95d479851
1f177489-4b16-670e-819d-4cf95d479851
1f177489-4b16-67e0-819d-4cf95d479851
1f177489-4b16-68b2-819d-4cf95d479851
1f177489-4b16-697a-819d-4cf95d479851
1f177489-4b16-6a4c-819d-4cf95d479851
1f177489-4b16-6b14-819d-4cf95d479851
1f177489-4b16-6c86-819d-4cf95d479851
1f177489-4b16-6d62-819d-4cf95d479851
1f177489-4b16-6e2a-819d-4cf95d479851
1f177489-4b16-6ef2-819d-4cf95d479851
1f177489-4b16-6fba-819d-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)

94b170a0-7748-11f1-819d-4cf95d479851
94b17104-7748-11f1-819d-4cf95d479851
94b17168-7748-11f1-819d-4cf95d479851
94b171cc-7748-11f1-819d-4cf95d479851
94b17226-7748-11f1-819d-4cf95d479851
94b1728a-7748-11f1-819d-4cf95d479851
94b172e4-7748-11f1-819d-4cf95d479851
94b17348-7748-11f1-819d-4cf95d479851
94b173ac-7748-11f1-819d-4cf95d479851
94b17406-7748-11f1-819d-4cf95d479851
94b17474-7748-11f1-819d-4cf95d479851
94b174ce-7748-11f1-819d-4cf95d479851
94b17532-7748-11f1-819d-4cf95d479851
94b1758c-7748-11f1-819d-4cf95d479851
94b17604-7748-11f1-819d-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)

e49b1f04-6000-890b-87ea-5ce32bd83b97
bbb72004-6000-890b-87ea-5ce32bd83b97
8fbe2104-6000-890b-87ea-5ce32bd83b97
44932204-6000-890b-87ea-5ce32bd83b97
82ad2304-6000-890b-87ea-5ce32bd83b97
3cd52404-6000-890b-87ea-5ce32bd83b97
bd5c2504-6000-890b-87ea-5ce32bd83b97
1f0d2604-6000-890b-87ea-5ce32bd83b97
2e9b2704-6000-890b-87ea-5ce32bd83b97
b2b32804-6000-890b-87ea-5ce32bd83b97
51182904-6000-890b-87ea-5ce32bd83b97
1c9d2a04-6000-890b-87ea-5ce32bd83b97
01712b04-6000-890b-87ea-5ce32bd83b97
4a212c04-6000-890b-87ea-5ce32bd83b97
40322d04-6000-890b-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)

98191ce9-3a01-4150-ab9f-18dda5da6001
e609f700-9578-4c8e-9dbd-d3eacd9b86ff
a9a44d6b-bc7a-4fa6-8908-a06d6985c000
4253150d-48c5-41fa-8ef4-d13f85961da7
b963dee6-cef4-4a5d-bcc6-326aa23d087e
9d8003e5-a2e1-4be5-a364-e89cab03df56
2d4f8e45-ecf7-4f5e-a118-fb54d2bb1eaf
ddb9d467-ecf2-4317-a306-0002e6f545fb
be9634d9-8c16-4f99-800a-12009b283eb0
9e9fd8e6-b8fa-4a66-ac7b-9189c30cd41b
d8c6aca5-e672-4889-9131-bc7b744bfb15
0c127cdd-3ad5-46c1-8e42-88cfee9f565e
37325672-0bc2-473d-ac2b-25487d743a3e
91844555-1347-4da3-8cd7-fa2e298ec4bd
25fe0fe1-f875-4b7a-bb66-15da950c98d5

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: