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)

01a07f0c-ef2b-76c9-91f9-8e2a5b96bdf0
01a07f0c-ef2b-785f-958c-31658bf25f5e
01a07f0c-ef2b-799e-97e1-decb1a97c434
01a07f0c-ef2b-7ac1-aca6-31396970549c
01a07f0c-ef2b-7bdc-89a2-0bdcf549077e
01a07f0c-ef2b-7cfa-8207-41cf7e5779e3
01a07f0c-ef2b-7e0d-badf-b55604573b5e
01a07f0c-ef2b-7f23-b50f-1b5fe822fdc0
01a07f0c-ef2c-703e-9d3b-ba5b6f424153
01a07f0c-ef2c-7159-b3bd-2b52ec1fb213
01a07f0c-ef2c-7273-92c9-c1d58098dfa9
01a07f0c-ef2c-738e-b79f-692f95e14954
01a07f0c-ef2c-74a8-a7d0-31af9c41cf39
01a07f0c-ef2c-75c3-bab3-95ffb1991d69
01a07f0c-ef2c-76de-b346-e53ac736666e

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)

1f1ab34f-cbff-6b56-ac48-4cf95d479851
1f1ab34f-cbff-6cfa-ac48-4cf95d479851
1f1ab34f-cbff-6dd6-ac48-4cf95d479851
1f1ab34f-cbff-6e9e-ac48-4cf95d479851
1f1ab34f-cbff-6f66-ac48-4cf95d479851
1f1ab34f-cc00-6024-ac48-4cf95d479851
1f1ab34f-cc00-60e2-ac48-4cf95d479851
1f1ab34f-cc00-61a0-ac48-4cf95d479851
1f1ab34f-cc00-6254-ac48-4cf95d479851
1f1ab34f-cc00-6312-ac48-4cf95d479851
1f1ab34f-cc00-645c-ac48-4cf95d479851
1f1ab34f-cc00-6524-ac48-4cf95d479851
1f1ab34f-cc00-65e2-ac48-4cf95d479851
1f1ab34f-cc00-66a0-ac48-4cf95d479851
1f1ab34f-cc00-675e-ac48-4cf95d479851

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)

fcc00830-ab34-11f1-ac48-4cf95d479851
fcc00894-ab34-11f1-ac48-4cf95d479851
fcc00902-ab34-11f1-ac48-4cf95d479851
fcc00966-ab34-11f1-ac48-4cf95d479851
fcc009c0-ab34-11f1-ac48-4cf95d479851
fcc00a24-ab34-11f1-ac48-4cf95d479851
fcc00a7e-ab34-11f1-ac48-4cf95d479851
fcc00ad8-ab34-11f1-ac48-4cf95d479851
fcc00b3c-ab34-11f1-ac48-4cf95d479851
fcc00b96-ab34-11f1-ac48-4cf95d479851
fcc00bf0-ab34-11f1-ac48-4cf95d479851
fcc00c54-ab34-11f1-ac48-4cf95d479851
fcc00cae-ab34-11f1-ac48-4cf95d479851
fcc00d12-ab34-11f1-ac48-4cf95d479851
fcc00d76-ab34-11f1-ac48-4cf95d479851

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)

fc903a31-ce00-8b0f-87ea-5ce32bd83b97
34253b31-ce00-8b0f-87ea-5ce32bd83b97
03d13c31-ce00-8b0f-87ea-5ce32bd83b97
e0213e31-ce00-8b0f-87ea-5ce32bd83b97
fe5b3f31-ce00-8b0f-87ea-5ce32bd83b97
21064031-ce00-8b0f-87ea-5ce32bd83b97
74024131-ce00-8b0f-87ea-5ce32bd83b97
0d5d4231-ce00-8b0f-87ea-5ce32bd83b97
5a754331-ce00-8b0f-87ea-5ce32bd83b97
95104431-ce00-8b0f-87ea-5ce32bd83b97
02ac4531-ce00-8b0f-87ea-5ce32bd83b97
1b384631-ce00-8b0f-87ea-5ce32bd83b97
e9ab4731-ce00-8b0f-87ea-5ce32bd83b97
8e644831-ce00-8b0f-87ea-5ce32bd83b97
38a94931-ce00-8b0f-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)

4b6dd6f7-eb40-4677-ae40-290674169f8c
e64ee5c7-9546-47cb-92ad-29fa5f0d1615
053a039c-2ff1-4313-8504-a56632939fa3
c0208423-3154-41f6-9131-1851dac4730f
f4482b7c-89c2-4396-9a88-30e4be819dcc
304a92af-9af1-46b8-abce-fbf94872a8f1
9e2993ae-2704-4433-9dcb-ac0bb2527e89
6ed4484e-609d-4d55-b24e-e14863c6fc3e
9f75fcc1-2e0b-4fec-8a0b-b7bb96467de5
e50b72f5-4a60-4f11-a44f-b109971e0130
9dc388e4-d88b-4372-956a-8beb32e9e32d
1415bc9f-9e83-4655-b926-02d6bf7cdb1f
97ea6fee-4765-48f7-ad04-42cbcf6a94e9
9de370c2-7419-4b8e-8364-03f07229d5e3
7d53e9c5-db29-4682-8f3d-2a718f0de29e

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: