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)

019f5ac4-9696-7a09-a257-bac820ce0879
019f5ac4-9696-7bc3-8f1d-5a1552646f27
019f5ac4-9696-7cfa-9b5e-736701147a37
019f5ac4-9696-7e7f-b0fa-a8d0c91729f0
019f5ac4-9696-7fd8-9719-cb3b2e6624c2
019f5ac4-9697-714c-9eb7-51c30ae5922d
019f5ac4-9697-7294-8459-24c2f097d452
019f5ac4-9697-73bf-a4c3-574c0d375599
019f5ac4-9697-74de-914f-e8886b4fe6be
019f5ac4-9697-75f4-b0f5-8eb21477abc2
019f5ac4-9697-770b-b3c1-8a32a8831cc9
019f5ac4-9697-781d-9981-e261ba4f3994
019f5ac4-9697-7934-a4a9-4b4812c045f1
019f5ac4-9697-7a4a-a7f7-a4756c60b6a9
019f5ac4-9697-7b5d-9b37-701738362dc0

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)

1f17e9bb-2bbc-6c9e-92c4-4cf95d479851
1f17e9bb-2bbc-6eb0-92c4-4cf95d479851
1f17e9bb-2bbc-6fa0-92c4-4cf95d479851
1f17e9bb-2bbd-6072-92c4-4cf95d479851
1f17e9bb-2bbd-613a-92c4-4cf95d479851
1f17e9bb-2bbd-6202-92c4-4cf95d479851
1f17e9bb-2bbd-62ca-92c4-4cf95d479851
1f17e9bb-2bbd-6392-92c4-4cf95d479851
1f17e9bb-2bbd-645a-92c4-4cf95d479851
1f17e9bb-2bbd-6522-92c4-4cf95d479851
1f17e9bb-2bbd-6676-92c4-4cf95d479851
1f17e9bb-2bbd-6752-92c4-4cf95d479851
1f17e9bb-2bbd-681a-92c4-4cf95d479851
1f17e9bb-2bbd-68d8-92c4-4cf95d479851
1f17e9bb-2bbd-6996-92c4-4cf95d479851

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)

b2bbda7c-7e9b-11f1-92c4-4cf95d479851
b2bbdaea-7e9b-11f1-92c4-4cf95d479851
b2bbdb58-7e9b-11f1-92c4-4cf95d479851
b2bbdbc6-7e9b-11f1-92c4-4cf95d479851
b2bbdc2a-7e9b-11f1-92c4-4cf95d479851
b2bbdc8e-7e9b-11f1-92c4-4cf95d479851
b2bbdcf2-7e9b-11f1-92c4-4cf95d479851
b2bbdd4c-7e9b-11f1-92c4-4cf95d479851
b2bbddb0-7e9b-11f1-92c4-4cf95d479851
b2bbde14-7e9b-11f1-92c4-4cf95d479851
b2bbde78-7e9b-11f1-92c4-4cf95d479851
b2bbdedc-7e9b-11f1-92c4-4cf95d479851
b2bbdf4a-7e9b-11f1-92c4-4cf95d479851
b2bbdfae-7e9b-11f1-92c4-4cf95d479851
b2bbe012-7e9b-11f1-92c4-4cf95d479851

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)

1300e328-2e02-820c-87ea-5ce32bd83b97
fb9de428-2e02-820c-87ea-5ce32bd83b97
47a9e528-2e02-820c-87ea-5ce32bd83b97
564be628-2e02-820c-87ea-5ce32bd83b97
a3f0e728-2e02-820c-87ea-5ce32bd83b97
325ce828-2e02-820c-87ea-5ce32bd83b97
3591e928-2e02-820c-87ea-5ce32bd83b97
046cea28-2e02-820c-87ea-5ce32bd83b97
5bd2eb28-2e02-820c-87ea-5ce32bd83b97
e53cec28-2e02-820c-87ea-5ce32bd83b97
7231ed28-2e02-820c-87ea-5ce32bd83b97
801bee28-2e02-820c-87ea-5ce32bd83b97
81afef28-2e02-820c-87ea-5ce32bd83b97
719ef028-2e02-820c-87ea-5ce32bd83b97
3fe0f128-2e02-820c-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)

e732c001-165e-47eb-af81-d4dc23aa92ae
5b6e129c-9807-4818-8e90-8c12080e7827
bf2f272a-4e33-478e-949d-d1e766d1beb4
656e5958-3815-4a56-bef7-da178da3fbe8
d7d1cc40-40e3-4e0f-b42b-c55a801a42e2
758d69a7-fd0e-4a65-98a0-e4a12d77eba5
7fb641b1-7435-4423-9f4a-3b476d1ff52a
e06fa6ab-7808-4fc0-a801-49214df4e0cb
a56e6ba8-1330-48a0-9bc7-76891db8c356
288be6c7-e93c-436a-afc4-19f6bddbd8ad
3c6f4997-1a9e-44f3-b4e0-f0ed1dfb6a46
aecf7009-a45e-4893-b98f-ff8f440d5a93
25d59991-f9b0-4a1b-aff1-199da893167d
d1a6238c-3d4f-446e-8f42-a221d9fea61e
2efefba3-3001-462e-b540-a5c78b9f8cf1

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: