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)

019de0cc-dc68-7673-b28d-5281b0b10827
019de0cc-dc68-7846-ab60-4d3619e749d2
019de0cc-dc68-7996-9715-46476c39b7ee
019de0cc-dc68-7ae2-bc74-2939b406a5e0
019de0cc-dc68-7c09-9fb2-c8fb1d1da271
019de0cc-dc68-7d3c-9a07-5e091ee97e3c
019de0cc-dc68-7e63-9f79-e18ff2619841
019de0cc-dc68-7fa2-91c6-442d731041c4
019de0cc-dc69-70da-b17c-f3311305deed
019de0cc-dc69-7211-8e5f-626053ba0445
019de0cc-dc69-7350-ab5f-10a367e7824d
019de0cc-dc69-7477-936e-c399d661ea14
019de0cc-dc69-75bb-a40e-0e6997211ef8
019de0cc-dc69-76de-b136-72915ccd63ba
019de0cc-dc69-7811-b378-0dbfb07d1b20

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)

1f144ef5-5e31-6f26-a074-4cf95d479851
1f144ef5-5e32-614c-a074-4cf95d479851
1f144ef5-5e32-6246-a074-4cf95d479851
1f144ef5-5e32-6318-a074-4cf95d479851
1f144ef5-5e32-63ea-a074-4cf95d479851
1f144ef5-5e32-64d0-a074-4cf95d479851
1f144ef5-5e32-6638-a074-4cf95d479851
1f144ef5-5e32-67aa-a074-4cf95d479851
1f144ef5-5e32-6890-a074-4cf95d479851
1f144ef5-5e32-6962-a074-4cf95d479851
1f144ef5-5e32-6aac-a074-4cf95d479851
1f144ef5-5e32-6b7e-a074-4cf95d479851
1f144ef5-5e32-6c6e-a074-4cf95d479851
1f144ef5-5e32-6dd6-a074-4cf95d479851
1f144ef5-5e32-6f16-a074-4cf95d479851

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)

7dba7afd-6fd1-4a3e-9135-e07cfd0afad0
f01ee355-7be4-4aba-8d35-5b9c8426d62d
516503ca-47d2-4833-8243-e9a503593306
68aa4a09-1990-4285-a15d-911a20ab72c2
3ec18020-d60a-48ea-92fd-f55d77d86229
2680b8d2-88e2-4d4d-aea0-9bdbe9d60420
11729d40-e060-416a-9d00-d66bb621f421
99bc7afd-c739-4af4-b635-97f37ddf2e4f
da8c4cfc-6cf0-4aa8-a80d-16763c0ce6a6
5f8a5c3d-ba89-4964-a99c-a6fc0e48f89a
5eff5d33-7633-456a-805e-2040a5447840
64431718-0b61-4890-b6d8-1eb90b58f521
71d11353-bfee-4981-9dc1-68af9799a5f8
3005fc91-bf0b-4866-ae41-1130cd8ad48f
2986f192-e668-4942-ae3c-90fb8d1e4f80

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)

55e334e8-44ef-11f1-a074-4cf95d479851
55e33588-44ef-11f1-a074-4cf95d479851
55e335f6-44ef-11f1-a074-4cf95d479851
55e3365a-44ef-11f1-a074-4cf95d479851
55e336be-44ef-11f1-a074-4cf95d479851
55e33718-44ef-11f1-a074-4cf95d479851
55e33786-44ef-11f1-a074-4cf95d479851
55e337ea-44ef-11f1-a074-4cf95d479851
55e33858-44ef-11f1-a074-4cf95d479851
55e338c6-44ef-11f1-a074-4cf95d479851
55e3392a-44ef-11f1-a074-4cf95d479851
55e3398e-44ef-11f1-a074-4cf95d479851
55e339f2-44ef-11f1-a074-4cf95d479851
55e33a7e-44ef-11f1-a074-4cf95d479851
55e33b0a-44ef-11f1-a074-4cf95d479851

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)

04a5670f-9705-8807-87ea-5ce32bd83b97
ed3e680f-9705-8807-87ea-5ce32bd83b97
40b8690f-9705-8807-87ea-5ce32bd83b97
adcb6a0f-9705-8807-87ea-5ce32bd83b97
39736b0f-9705-8807-87ea-5ce32bd83b97
2f366c0f-9705-8807-87ea-5ce32bd83b97
e1b16d0f-9705-8807-87ea-5ce32bd83b97
0cf96e0f-9705-8807-87ea-5ce32bd83b97
75e06f0f-9705-8807-87ea-5ce32bd83b97
13a2700f-9705-8807-87ea-5ce32bd83b97
6119710f-9705-8807-87ea-5ce32bd83b97
e11a720f-9705-8807-87ea-5ce32bd83b97
a49b730f-9705-8807-87ea-5ce32bd83b97
0681740f-9705-8807-87ea-5ce32bd83b97
5d04750f-9705-8807-87ea-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: