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)

01a1d554-9eee-7e46-9c7e-c5de87ce7d5d
01a1d554-9eee-7011-b542-1caf91c837cb
01a1d554-9eef-7159-820e-52ea66c405e2
01a1d554-9eef-727b-9946-2d238e5ae0b6
01a1d554-9eef-7396-b382-5929497ef42d
01a1d554-9eef-74ad-ae2f-72f9fd1d37b5
01a1d554-9eef-75c7-893b-340bf8de4b85
01a1d554-9eef-76de-8f22-b581f7744067
01a1d554-9eef-77f0-9c2a-de53db413e04
01a1d554-9eef-7907-af59-dcbdbe484e0e
01a1d554-9eef-7a1d-8383-847855322f1a
01a1d554-9eef-7b30-aba6-582bd39b3196
01a1d554-9eef-7c46-b729-41d950d1d660
01a1d554-9eef-7d59-8b8f-fee3c8c694ba
01a1d554-9eef-7e6b-8bca-e78e3a9cd176

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)

1f1df6f4-d01c-6180-8890-4cf95d479851
1f1df6f4-d01c-6388-8890-4cf95d479851
1f1df6f4-d01c-6482-8890-4cf95d479851
1f1df6f4-d01c-655e-8890-4cf95d479851
1f1df6f4-d01c-6630-8890-4cf95d479851
1f1df6f4-d01c-6702-8890-4cf95d479851
1f1df6f4-d01c-67de-8890-4cf95d479851
1f1df6f4-d01c-68a6-8890-4cf95d479851
1f1df6f4-d01c-6982-8890-4cf95d479851
1f1df6f4-d01c-6a54-8890-4cf95d479851
1f1df6f4-d01c-6bbc-8890-4cf95d479851
1f1df6f4-d01c-6ca2-8890-4cf95d479851
1f1df6f4-d01c-6d7e-8890-4cf95d479851
1f1df6f4-d01c-6e5a-8890-4cf95d479851
1f1df6f4-d01c-6f2c-8890-4cf95d479851

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)

4d01d012-df6f-11f1-8890-4cf95d479851
4d01d076-df6f-11f1-8890-4cf95d479851
4d01d0da-df6f-11f1-8890-4cf95d479851
4d01d148-df6f-11f1-8890-4cf95d479851
4d01d1b6-df6f-11f1-8890-4cf95d479851
4d01d21a-df6f-11f1-8890-4cf95d479851
4d01d274-df6f-11f1-8890-4cf95d479851
4d01d2d8-df6f-11f1-8890-4cf95d479851
4d01d332-df6f-11f1-8890-4cf95d479851
4d01d396-df6f-11f1-8890-4cf95d479851
4d01d3fa-df6f-11f1-8890-4cf95d479851
4d01d454-df6f-11f1-8890-4cf95d479851
4d01d4ae-df6f-11f1-8890-4cf95d479851
4d01d512-df6f-11f1-8890-4cf95d479851
4d01d576-df6f-11f1-8890-4cf95d479851

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)

03f0270f-6b03-8d13-87ea-5ce32bd83b97
5c8e280f-6b03-8d13-87ea-5ce32bd83b97
a657290f-6b03-8d13-87ea-5ce32bd83b97
0baf2a0f-6b03-8d13-87ea-5ce32bd83b97
1ac62b0f-6b03-8d13-87ea-5ce32bd83b97
d56f2c0f-6b03-8d13-87ea-5ce32bd83b97
fc532d0f-6b03-8d13-87ea-5ce32bd83b97
118f2e0f-6b03-8d13-87ea-5ce32bd83b97
8f202f0f-6b03-8d13-87ea-5ce32bd83b97
ad8f300f-6b03-8d13-87ea-5ce32bd83b97
631d310f-6b03-8d13-87ea-5ce32bd83b97
e386320f-6b03-8d13-87ea-5ce32bd83b97
1462330f-6b03-8d13-87ea-5ce32bd83b97
9926340f-6b03-8d13-87ea-5ce32bd83b97
89c6350f-6b03-8d13-87ea-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)

b4c82ae6-a5b0-436d-8faa-843f7055b789
5b2869bd-25c2-4291-9d65-f588ac629650
766f16e0-b888-4530-947f-216b9ec8dc35
8c95386d-709a-4532-8579-feb971130d4a
8a9dfe18-b912-407f-9429-9a3325c9a028
5bd12b15-555a-45f4-8803-0762669e696b
6596ef4d-1c9f-4d38-b689-47c93a0c2144
8ee2628e-142b-45aa-89ed-793bee3d667c
37b8efad-4560-47c0-a1fe-871168fc4b3c
66413a32-9352-4147-b6d6-2f5fd6c3356a
ff9357ba-02e3-4a30-b1d3-b91f519f493c
93584f1c-c3b9-4ebb-98ec-1dd8492ebdfc
b2bd21e5-d40c-41e2-bedf-75d4fe2ec06a
91076504-e7cd-42a6-b5e0-af053497651f
b5828bb7-7a02-488e-9624-f107d2417d76

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: