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)

019b4762-3c8f-7667-ac97-391d9dc5fedf
019b4762-3c8f-7809-9171-5a68f7604196
019b4762-3c8f-7948-9b84-431df9c4769e
019b4762-3c8f-7a6f-b624-f5d14a25e9a6
019b4762-3c8f-7b8a-b890-d9b1ecf73560
019b4762-3c8f-7ca8-9488-3b17ba3a3809
019b4762-3c8f-7dc7-8d0c-584ccfa907da
019b4762-3c8f-7ee2-828a-afeb6757aea5
019b4762-3c8f-7ffc-ba73-b53ac3b36cb5
019b4762-3c90-711b-82a9-131aecf1b605
019b4762-3c90-723a-a79b-1368a6ad9cd5
019b4762-3c90-7354-9a8b-1848d20d01c8
019b4762-3c90-746f-a10f-1fe69d9e5bc9
019b4762-3c90-758e-911c-69f3b2eac973
019b4762-3c90-76a8-8dfb-52a25d63f5d9

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)

1f0df668-0df0-6e68-8946-4cf95d479851
1f0df668-0df0-6ff8-8946-4cf95d479851
1f0df668-0df1-60de-8946-4cf95d479851
1f0df668-0df1-61a6-8946-4cf95d479851
1f0df668-0df1-626e-8946-4cf95d479851
1f0df668-0df1-632c-8946-4cf95d479851
1f0df668-0df1-63f4-8946-4cf95d479851
1f0df668-0df1-64b2-8946-4cf95d479851
1f0df668-0df1-6570-8946-4cf95d479851
1f0df668-0df1-6638-8946-4cf95d479851
1f0df668-0df1-6796-8946-4cf95d479851
1f0df668-0df1-6868-8946-4cf95d479851
1f0df668-0df1-6930-8946-4cf95d479851
1f0df668-0df1-69e4-8946-4cf95d479851
1f0df668-0df1-6aa2-8946-4cf95d479851

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)

995ccdd3-99c8-4e1c-bcb4-6f2379e3cd6e
7763c79e-b978-425f-b643-775242b3a1e0
546e158e-a5cb-4470-b287-a8a9f731a507
6fbe8d91-9330-4852-a8ae-2d7ae1b315cf
55ee4ecd-285d-4dc1-8bd0-cde3320a79b1
3c394ce1-f545-4b29-8d30-17b3cc966fdd
b4a905ab-265b-4451-b9db-94b2ae3ee419
f6d9c53a-b1c7-40ab-b35b-7af0ca3723ba
53cb78c6-c94f-47a1-9256-6e2055c2aae3
1f8e27b7-911b-44c5-8e5d-5d6682460de6
cb581fd3-489f-4f77-a413-47033f1d61c7
1812765b-aa5d-4ffd-8473-0fd9c78ad0ac
ed96378f-b853-4404-8af3-c4ecec41da1f
36948b8f-834f-49ab-95ca-247a32755234
b500bd3b-7bb7-4133-afc5-6747b51e2058

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)

80df1fa2-df66-11f0-8946-4cf95d479851
80df2010-df66-11f0-8946-4cf95d479851
80df206a-df66-11f0-8946-4cf95d479851
80df20ce-df66-11f0-8946-4cf95d479851
80df2132-df66-11f0-8946-4cf95d479851
80df218c-df66-11f0-8946-4cf95d479851
80df21e6-df66-11f0-8946-4cf95d479851
80df224a-df66-11f0-8946-4cf95d479851
80df22b8-df66-11f0-8946-4cf95d479851
80df2326-df66-11f0-8946-4cf95d479851
80df2380-df66-11f0-8946-4cf95d479851
80df23e4-df66-11f0-8946-4cf95d479851
80df2448-df66-11f0-8946-4cf95d479851
80df24ac-df66-11f0-8946-4cf95d479851
80df2510-df66-11f0-8946-4cf95d479851

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)

76c80613-6704-8416-87e9-5ce32bd83b97
5a740713-6704-8416-87e9-5ce32bd83b97
aef00813-6704-8416-87e9-5ce32bd83b97
65090913-6704-8416-87e9-5ce32bd83b97
a7310a13-6704-8416-87e9-5ce32bd83b97
a4c40b13-6704-8416-87e9-5ce32bd83b97
06390d13-6704-8416-87e9-5ce32bd83b97
fd110e13-6704-8416-87e9-5ce32bd83b97
99a00f13-6704-8416-87e9-5ce32bd83b97
da911013-6704-8416-87e9-5ce32bd83b97
14021113-6704-8416-87e9-5ce32bd83b97
31ac1213-6704-8416-87e9-5ce32bd83b97
ec0b1313-6704-8416-87e9-5ce32bd83b97
4f0b1413-6704-8416-87e9-5ce32bd83b97
a8721513-6704-8416-87e9-5ce32bd83b97

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: