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)

019cf9a6-6e89-7713-84d1-6e82fb2d2fd5
019cf9a6-6e89-78ad-8fff-9064a5ef94c1
019cf9a6-6e89-79f0-9ae1-2f7eb03c7279
019cf9a6-6e89-7b13-86c2-ecd4534d2523
019cf9a6-6e89-7c2e-bcce-3ebd07aecc58
019cf9a6-6e89-7d44-8334-b619271d3c80
019cf9a6-6e89-7e5f-a6fd-62f50eb56959
019cf9a6-6e89-7f75-ab00-4010ccd304c1
019cf9a6-6e8a-7140-b978-ab4afa73adfb
019cf9a6-6e8a-7263-8b20-4cbd92d692d3
019cf9a6-6e8a-737d-bd4d-55a8c9e24da1
019cf9a6-6e8a-75d3-bd6c-7a594e0ef2a5
019cf9a6-6e8a-76ee-8ac6-1300cb0b0e13
019cf9a6-6e8a-7809-b33e-353d571926cd
019cf9a6-6e8a-7927-a09f-e7dca4b9aced

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)

1f121aa0-8bf4-68c2-a2c8-4cf95d479851
1f121aa0-8bf4-6a66-a2c8-4cf95d479851
1f121aa0-8bf4-6b56-a2c8-4cf95d479851
1f121aa0-8bf4-6c32-a2c8-4cf95d479851
1f121aa0-8bf4-6d0e-a2c8-4cf95d479851
1f121aa0-8bf4-6de0-a2c8-4cf95d479851
1f121aa0-8bf4-6eb2-a2c8-4cf95d479851
1f121aa0-8bf4-6f84-a2c8-4cf95d479851
1f121aa0-8bf5-6380-a2c8-4cf95d479851
1f121aa0-8bf5-6470-a2c8-4cf95d479851
1f121aa0-8bf5-65c4-a2c8-4cf95d479851
1f121aa0-8bf5-66a0-a2c8-4cf95d479851
1f121aa0-8bf5-6a4c-a2c8-4cf95d479851
1f121aa0-8bf5-6b46-a2c8-4cf95d479851
1f121aa0-8bf5-6c18-a2c8-4cf95d479851

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)

4c797242-d486-43e7-b8f8-ee6ed649f4c2
63771c87-d839-4c63-8303-ba2850b05596
b38c3645-96ea-4bd5-ad3d-a3e2596e6200
1c305a1f-c437-4eaa-8bd5-803c25d22a46
e77b1d9b-725b-4fb7-9f3d-6f13fb94a50a
dec7689c-8a99-488d-ac65-fbe9d40c4f3c
2845ad7c-3299-498f-9b54-de667f15ae52
359885c1-89d9-48d8-b5ff-f42ec29f4929
bf8f4db9-5bae-422e-9c17-a3743c5cd549
d8b94909-e202-43a4-94bc-636f8a863d79
2fa5f5f6-b7e9-4744-a5b3-319252993069
92f5069d-8bd8-4cd8-9428-06113fb8db7a
6667486c-4c95-435a-aa85-161682f34c5e
49e92592-c1e3-4d52-afb1-73059927f299
96b1c344-14fd-4a01-b92f-07d520d3ace7

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)

08bf62da-21aa-11f1-a2c8-4cf95d479851
08bf6352-21aa-11f1-a2c8-4cf95d479851
08bf63c0-21aa-11f1-a2c8-4cf95d479851
08bf642e-21aa-11f1-a2c8-4cf95d479851
08bf649c-21aa-11f1-a2c8-4cf95d479851
08bf64f6-21aa-11f1-a2c8-4cf95d479851
08bf6564-21aa-11f1-a2c8-4cf95d479851
08bf65c8-21aa-11f1-a2c8-4cf95d479851
08bf662c-21aa-11f1-a2c8-4cf95d479851
08bf66a4-21aa-11f1-a2c8-4cf95d479851
08bf6708-21aa-11f1-a2c8-4cf95d479851
08bf6776-21aa-11f1-a2c8-4cf95d479851
08bf67da-21aa-11f1-a2c8-4cf95d479851
08bf6848-21aa-11f1-a2c8-4cf95d479851
08bf68b6-21aa-11f1-a2c8-4cf95d479851

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)

f3f10300-9d00-8c04-87ea-5ce32bd83b97
f9a30400-9d00-8c04-87ea-5ce32bd83b97
90fe0500-9d00-8c04-87ea-5ce32bd83b97
72c80600-9d00-8c04-87ea-5ce32bd83b97
891f0700-9d00-8c04-87ea-5ce32bd83b97
fe600800-9d00-8c04-87ea-5ce32bd83b97
a07c0900-9d00-8c04-87ea-5ce32bd83b97
c7df0a00-9d00-8c04-87ea-5ce32bd83b97
8b430b00-9d00-8c04-87ea-5ce32bd83b97
a4d80c00-9d00-8c04-87ea-5ce32bd83b97
a4430d00-9d00-8c04-87ea-5ce32bd83b97
a26a0e00-9d00-8c04-87ea-5ce32bd83b97
f5dc0f00-9d00-8c04-87ea-5ce32bd83b97
9e9e1000-9d00-8c04-87ea-5ce32bd83b97
eeaa1100-9d00-8c04-87ea-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: