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)

01a01fa0-90db-7717-be47-83a6fb92c463
01a01fa0-90db-7934-90ed-09742eeea0a9
01a01fa0-90db-7a6f-8d99-d37efa07e5a1
01a01fa0-90db-7ba6-9aa0-91ebf01f38b2
01a01fa0-90db-7cda-84b7-ab1d45d6361c
01a01fa0-90db-7df4-98a5-ca8778603b73
01a01fa0-90db-7f0b-981d-25e24399f5a3
01a01fa0-90dc-7021-b07f-7d7016457b40
01a01fa0-90dc-7138-9567-45c219d55179
01a01fa0-90dc-724a-a2e7-307fa95ccdfd
01a01fa0-90dc-735d-b9c4-2aae384563d1
01a01fa0-90dc-7473-8c9c-9cd2090f3bf1
01a01fa0-90dc-7586-80de-0be050aae181
01a01fa0-90dc-769c-82ed-6febeeaacbc7
01a01fa0-90dc-77b3-9cfc-b626d529324e

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)

1f19ca58-39be-6890-8e22-4cf95d479851
1f19ca58-39be-6a5c-8e22-4cf95d479851
1f19ca58-39be-6b42-8e22-4cf95d479851
1f19ca58-39be-6c0a-8e22-4cf95d479851
1f19ca58-39be-6cd2-8e22-4cf95d479851
1f19ca58-39be-6d9a-8e22-4cf95d479851
1f19ca58-39be-6e62-8e22-4cf95d479851
1f19ca58-39be-6f2a-8e22-4cf95d479851
1f19ca58-39be-6ffc-8e22-4cf95d479851
1f19ca58-39bf-60ba-8e22-4cf95d479851
1f19ca58-39bf-620e-8e22-4cf95d479851
1f19ca58-39bf-62ea-8e22-4cf95d479851
1f19ca58-39bf-63a8-8e22-4cf95d479851
1f19ca58-39bf-645c-8e22-4cf95d479851
1f19ca58-39bf-651a-8e22-4cf95d479851

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)

839bf5ec-9ca5-11f1-8e22-4cf95d479851
839bf650-9ca5-11f1-8e22-4cf95d479851
839bf6b4-9ca5-11f1-8e22-4cf95d479851
839bf718-9ca5-11f1-8e22-4cf95d479851
839bf772-9ca5-11f1-8e22-4cf95d479851
839bf7cc-9ca5-11f1-8e22-4cf95d479851
839bf826-9ca5-11f1-8e22-4cf95d479851
839bf88a-9ca5-11f1-8e22-4cf95d479851
839bf8e4-9ca5-11f1-8e22-4cf95d479851
839bf952-9ca5-11f1-8e22-4cf95d479851
839bf9c0-9ca5-11f1-8e22-4cf95d479851
839bfa24-9ca5-11f1-8e22-4cf95d479851
839bfa92-9ca5-11f1-8e22-4cf95d479851
839bfb00-9ca5-11f1-8e22-4cf95d479851
839bfb64-9ca5-11f1-8e22-4cf95d479851

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)

07a6ad1f-7403-880e-87ea-5ce32bd83b97
d67fae1f-7403-880e-87ea-5ce32bd83b97
ff58af1f-7403-880e-87ea-5ce32bd83b97
2849b01f-7403-880e-87ea-5ce32bd83b97
5455b11f-7403-880e-87ea-5ce32bd83b97
3496b21f-7403-880e-87ea-5ce32bd83b97
e72db31f-7403-880e-87ea-5ce32bd83b97
7a40b41f-7403-880e-87ea-5ce32bd83b97
2d8cb51f-7403-880e-87ea-5ce32bd83b97
3d1cb61f-7403-880e-87ea-5ce32bd83b97
9cd8b71f-7403-880e-87ea-5ce32bd83b97
38f8b81f-7403-880e-87ea-5ce32bd83b97
bc18b91f-7403-880e-87ea-5ce32bd83b97
9bd4ba1f-7403-880e-87ea-5ce32bd83b97
09c6bb1f-7403-880e-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)

bec2e487-505f-445e-a784-da8730f494b1
1a23e3d1-537a-450a-b82e-44ed6b3fc0c1
b81d17b9-3ecb-4c0c-b203-f2a414e3194a
af8a75d9-ae66-4b79-b58f-d5e5266b4a59
fe8a81fc-bbe3-47da-9e82-40bfeea2c3fe
1f6a2c45-02f4-4ffd-9019-ad14642cf485
91f763db-1ae6-4b24-92c2-0df4d90966d5
4bbed675-b03c-4450-ba21-507babf94a0c
19a82727-711c-4a9e-9b34-3e6cd03b6a3d
bc0f9047-0a8b-4f31-905f-fcb1cb317802
97edec1e-b210-44bf-8aec-6b378dc9e704
38b68d25-05ad-454d-a9f8-4c29204b8e0a
8f1689e6-8231-4f9d-9b32-fc2a12f3d648
9de0ef71-fce2-4377-9d2a-239404e33b4b
83fae4a0-6408-4507-862a-f7a715fb5471

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: