Current style number plate format
Memory tag
The first letter (known as the mnemonic) represents a broad area where the registration office was located, with the second letter representing the actual registering office within the region. These first 2 letters make up the memory tag (area code) and are a reference to the DVLA (Driver & Vehicle Licensing Agency) local office which was responsible for issuing the number plate.
Although all DVLA local offices (with the exception of DVLA Swansea) in England, Wales and Scotland were officially closed and moved online by the end of December 2013, number plates are still issued to new cars with a memory tag based on the region or area they were registered in.
The letters I, Q and Z are not used in the first 2 characters.
Age identifier
The two-digit age identifier make up the third and fourth characters on a current style number plate and follows the memory tag. The age identifier changes twice a year, in March and in September.
Vehicles registered between 1 March – 31 August use the the last two digits of the year they are registered in e.g a vehicle registered on 10 August 2021 would use the number “21” as the age identifier.
For vehicles registered between 1 September and 28 February in the following year, 50 is added to the previous age identifier value (21 + 50 = 71). So a vehicle registered on 8 November 2021 would use “71” as the its age identifier.
Random three-letter sequence
The final 3 letters on current style number plates are randomly generated to uniquely distinguish between vehicles that have been registered in the same area, and have the same age identifier (e.g. vehicles registered in Isle of Man between 01 Mar 2017 – 31 Aug 2017 would all share the same initial four characters “MN71”) .
The letters I and Q are excluded and not used in the last three randomly generated sequence; however, unlike with the memory tag, the character “Z” is allowed and used in the randomly generated three-letter sequence.
The current system should have sufficient numbers to run until 28 February 2051.