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)

019eef35-ba05-74ee-aa94-b2b03d357520
019eef35-ba05-76ad-833f-840b9b60b243
019eef35-ba05-7819-ae43-6d18681cd23b
019eef35-ba05-793c-a5e2-c5c69541b791
019eef35-ba05-7a57-9274-4046f1801df4
019eef35-ba05-7b75-bf89-8baf8ae96a24
019eef35-ba05-7c90-8048-2931730fa657
019eef35-ba05-7daa-98f2-14d9ad881eba
019eef35-ba05-7ec5-85bc-67a48d7ab68a
019eef35-ba05-7fe4-8069-5fd4296d6143
019eef35-ba06-70fe-a2f6-c85cd054d879
019eef35-ba06-7219-a3f8-0a6758857373
019eef35-ba06-7334-acdf-f56156bda413
019eef35-ba06-745f-a1b8-ade214605871
019eef35-ba06-7579-86c1-6980ebf0a9e3

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)

1f16e323-633d-6bc2-8e0d-4cf95d479851
1f16e323-633d-6ee2-8e0d-4cf95d479851
1f16e323-633d-6fdc-8e0d-4cf95d479851
1f16e323-633e-60ae-8e0d-4cf95d479851
1f16e323-633e-6180-8e0d-4cf95d479851
1f16e323-633e-6248-8e0d-4cf95d479851
1f16e323-633e-6310-8e0d-4cf95d479851
1f16e323-633e-63e2-8e0d-4cf95d479851
1f16e323-633e-64aa-8e0d-4cf95d479851
1f16e323-633e-6572-8e0d-4cf95d479851
1f16e323-633e-66ee-8e0d-4cf95d479851
1f16e323-633e-67d4-8e0d-4cf95d479851
1f16e323-633e-689c-8e0d-4cf95d479851
1f16e323-633e-696e-8e0d-4cf95d479851
1f16e323-633e-6a36-8e0d-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)

3633eb26-6e32-11f1-8e0d-4cf95d479851
3633eb9e-6e32-11f1-8e0d-4cf95d479851
3633ec0c-6e32-11f1-8e0d-4cf95d479851
3633ec84-6e32-11f1-8e0d-4cf95d479851
3633ecf2-6e32-11f1-8e0d-4cf95d479851
3633ed56-6e32-11f1-8e0d-4cf95d479851
3633edba-6e32-11f1-8e0d-4cf95d479851
3633ee1e-6e32-11f1-8e0d-4cf95d479851
3633ee96-6e32-11f1-8e0d-4cf95d479851
3633eefa-6e32-11f1-8e0d-4cf95d479851
3633ef5e-6e32-11f1-8e0d-4cf95d479851
3633efc2-6e32-11f1-8e0d-4cf95d479851
3633f026-6e32-11f1-8e0d-4cf95d479851
3633f08a-6e32-11f1-8e0d-4cf95d479851
3633f0ee-6e32-11f1-8e0d-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)

e8823310-d302-8d0a-87ea-5ce32bd83b97
ec3d3410-d302-8d0a-87ea-5ce32bd83b97
38773510-d302-8d0a-87ea-5ce32bd83b97
88823610-d302-8d0a-87ea-5ce32bd83b97
bed63710-d302-8d0a-87ea-5ce32bd83b97
e6653810-d302-8d0a-87ea-5ce32bd83b97
eb6f3910-d302-8d0a-87ea-5ce32bd83b97
fefa3a10-d302-8d0a-87ea-5ce32bd83b97
06003b10-d302-8d0a-87ea-5ce32bd83b97
e4353c10-d302-8d0a-87ea-5ce32bd83b97
5f953d10-d302-8d0a-87ea-5ce32bd83b97
84213e10-d302-8d0a-87ea-5ce32bd83b97
844d3f10-d302-8d0a-87ea-5ce32bd83b97
fb3c4010-d302-8d0a-87ea-5ce32bd83b97
1bd84110-d302-8d0a-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)

6a3df954-5722-4e92-9b6b-62f017543d30
ea654c3a-fc71-44b6-ba03-45f007cdd814
351f3610-792a-4951-8afe-3b085f15adda
5dacd3ec-4e1e-4fff-adec-c18f05cb7cd9
1d5af179-5682-4bf5-8c2c-411e05760d8f
8b8daba3-cd77-447e-a7f0-6214c421b46d
2cb24915-abc6-497a-9586-1bcdc3842bfb
7b4420b5-c377-4e05-b5c5-4ad7640942e2
cd59a2f2-7d27-4c38-9440-8de204d44cf3
0935d3a9-6089-4198-b423-84a41ef0391d
187e2593-5e77-4a54-bfb4-01fe6d8e7308
964a694a-85c1-47b3-8e6c-e352e45b9cfe
6496eed8-78ab-47ac-852f-e7899654c2c6
21fc069c-04a2-4b45-8363-4dc9f9a4cec0
bb4720ff-efb9-428b-97e7-20f9c6f2fd94

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: