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)

019de64f-a443-7063-a1df-8d15732fd611
019de64f-a444-7215-a4e9-928614db64a9
019de64f-a444-735d-99e4-97dc387db2d4
019de64f-a444-7488-9856-447288fb273a
019de64f-a444-75a2-860c-5d4e9967db81
019de64f-a444-76c1-bce4-0849c0750418
019de64f-a444-77dc-a77d-eddb79f6a4e1
019de64f-a444-78f6-beef-5637b1d05d17
019de64f-a444-7a11-8e98-50c6a0da2c25
019de64f-a444-7b2c-8d66-3e36b1268004
019de64f-a444-7c42-8c7a-13da0488f74d
019de64f-a444-7d59-a629-53ce73989306
019de64f-a444-7e6f-9748-7c3e619b4799
019de64f-a444-7f8a-9bac-3f20ee3c6ba2
019de64f-a445-70a0-8a83-acf3a8632703

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)

1f145c69-a820-6cd2-98b1-4cf95d479851
1f145c69-a820-6e62-98b1-4cf95d479851
1f145c69-a820-6f48-98b1-4cf95d479851
1f145c69-a821-6024-98b1-4cf95d479851
1f145c69-a821-60ec-98b1-4cf95d479851
1f145c69-a821-6326-98b1-4cf95d479851
1f145c69-a821-6420-98b1-4cf95d479851
1f145c69-a821-64e8-98b1-4cf95d479851
1f145c69-a821-65b0-98b1-4cf95d479851
1f145c69-a821-6678-98b1-4cf95d479851
1f145c69-a821-67b8-98b1-4cf95d479851
1f145c69-a821-6880-98b1-4cf95d479851
1f145c69-a821-6948-98b1-4cf95d479851
1f145c69-a821-6a10-98b1-4cf95d479851
1f145c69-a821-6ace-98b1-4cf95d479851

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)

4d360ace-32e3-43a0-b13a-75106181be9d
9cd0ff61-6af9-4273-974d-083a21af4c8c
4db9ae4d-1601-463e-9abe-fcf37975d87a
fb363ec8-d4e3-4964-a99c-024e2fc2323a
6a5cb680-cd5c-43f4-8b1d-eae17a2ee684
4d1558dd-e3cd-4f3f-8f7e-ccfd45ece001
5343315b-8b67-4252-acc0-27f3b63a36f7
06fe4b5b-028c-4216-a1c1-194c9591fcaf
9c3f27b7-5ae6-4aa0-852c-7a2d83a12173
e43abc10-ea4b-4fd1-8608-c9c7e99ec025
fd029c26-e606-4451-a7e1-1349edb01402
07fe4d99-fc94-4b0f-8a07-eb1ed5f8c00b
c111fd8f-dc1f-4a45-944b-0ef4e28af29e
bdf0409a-d22f-4462-9ae6-1e3b2c543d05
cc84d6a4-dc01-4431-b5ca-5111e3ee0487

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)

9a82203c-45c6-11f1-98b1-4cf95d479851
9a8220dc-45c6-11f1-98b1-4cf95d479851
9a822172-45c6-11f1-98b1-4cf95d479851
9a822208-45c6-11f1-98b1-4cf95d479851
9a822294-45c6-11f1-98b1-4cf95d479851
9a822320-45c6-11f1-98b1-4cf95d479851
9a8223c0-45c6-11f1-98b1-4cf95d479851
9a82244c-45c6-11f1-98b1-4cf95d479851
9a8224ec-45c6-11f1-98b1-4cf95d479851
9a822582-45c6-11f1-98b1-4cf95d479851
9a822618-45c6-11f1-98b1-4cf95d479851
9a8226a4-45c6-11f1-98b1-4cf95d479851
9a822730-45c6-11f1-98b1-4cf95d479851
9a82279e-45c6-11f1-98b1-4cf95d479851
9a82280c-45c6-11f1-98b1-4cf95d479851

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)

94c8530c-5c00-8a07-87ea-5ce32bd83b97
209c540c-5c00-8a07-87ea-5ce32bd83b97
55b1550c-5c00-8a07-87ea-5ce32bd83b97
2c82560c-5c00-8a07-87ea-5ce32bd83b97
9b64570c-5c00-8a07-87ea-5ce32bd83b97
5e99580c-5c00-8a07-87ea-5ce32bd83b97
e6d7590c-5c00-8a07-87ea-5ce32bd83b97
0e115a0c-5c00-8a07-87ea-5ce32bd83b97
23455b0c-5c00-8a07-87ea-5ce32bd83b97
05305c0c-5c00-8a07-87ea-5ce32bd83b97
e3fb5e0c-5c00-8a07-87ea-5ce32bd83b97
7c2f5f0c-5c00-8a07-87ea-5ce32bd83b97
8c31600c-5c00-8a07-87ea-5ce32bd83b97
ebb1610c-5c00-8a07-87ea-5ce32bd83b97
1088620c-5c00-8a07-87ea-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: