Imported Size Number Plates On UK Vehicles | Is It Legal??

Are Imported Size Number Plates Legal On UK Vehicles…?

Is it legal to mount imported size number plates on my UK spec car?

Small 4D 3mm UK Bespoke Legal Number Plates For Imported Vehicles

There have been a few recent customers get in contact and ask us this question and in this article, the team at JDM Plates will explain why it is actually illegal to mount imported size number plates on your UK spec vehicles and you could be fined up to £100 if stopped.

The Honda Civic, and in particular the Honda Civic EP3 was the main car being questioned. The Honda Civic is renowned for being owned by enthusiasts and many of them actually have smaller imported size number plates mounted to them; just search #hondacivicep3 #ep3 #hondacivic on Instagram and look at all of the rear number plate sizes – these sizes include:-

330mm x 178mm              (13’ x 7’)

330mm x 165mm              (13’ x 6.5’)

303mm x 152mm              (12’ x 6’)

However, there are many Honda’s within the UK that have been imported; the Honda Civic EP3, as well as the Honda Integra DC5 and Honda S2000 to name a few are actually part of this group. Due to this, some Honda models belong to both the JDM and UKDM categories which is presumably where the confusion comes from; this can sometimes cause a subjective interpretation with regards to number plate legislation and what size number plates you can legally mount! Smaller number plates do look so much better though!

Number Plate Legislation States…

Legislation does state that number plates for UK spec vehicles need to comply with the following specification:-

  • Character height to be 79mm.
  • Character width to be 50mm.
  • Character stroke to be 14mm.
  • The spacing between characters to be 11mm but the horizontal spacing between groups to be 33mm.
  • The vertical spacing between groups to be 19mm.
  • The minimum margin (horizontal and vertical) to be 11mm between the side and top of the characters and edge of the number plate.

UK Specification Guidelines

Considering the above dimensions, it can be calculated that the minimum size square number plate for a 7 digit registration that is to be mounted on a UK spec vehicle must be atleast:-


2 x 79mm high characters = 158mm
1 x 19mm vertical spacing between groups = 19mm
2 x 11mm vertical margins = 22mm

The total height of a square number plate which is to be mounted on a UK spec vehicle is therefore 199mm high.

What About Imported Vehicles…?

Imported size number plates and motorcycle number plates have the dimensions and spacing’s associated with the list below:-

  • Character height to be 64mm.
  • Character width to be 44mm.
  • Character stroke to be 10mm.
  • The spacing between characters to be 10mm but the horizontal spacing between groups to be 30mm.
  • The vertical spacing between groups to be 13mm.
  • The minimum margin, horizontal, to be 11mm and vertical, to be 11mm (top) and 11mm (bottom) between the side and top of the characters and edge of the number plate.

As the dimensions are somewhat smaller; it allows the overall plate to be condensed and made significantly shorter and narrower whilst still complying with relevant legislation. However, after further research, these dimensions can also be slightly smaller for imported vehicles; please see our number plate article for the smallest legal motorcycle number plates HERE!

On imported vehicles, the minimum margins are actually different – confusing I know! On the, Road Vehicles (Display of Registration Marks) Regulations 2001, the minimum outer margins and vertical spacing between groups can be as small as 5mm as opposed to 11mm for motorcycle! However, the bottom margin needs to be a minimum of 13mm; the company name and postcode can also be located within this margin.

Considering the dimensions listed in the aforementioned Regulation, it can be calculated that the minimum size square number plate for a 7 digit registration that is to be mounted on a JDM imported spec vehicle must be:-


2 x 64mm high characters = 128mm
1 x 5mm vertical spacing between groups = 5mm
1 x 5mm vertical margin (top) = 5mm
1 x 13mm vertical margin (bottom) = 13mm

The total height of a square number plate which is to be mounted on a JDM imported spec is therefore 151mm high; BNMA registered number plate suppliers tend to go as small as 152mm to ensure the plates meet the minimum size requirement.

But Can I Legally Mount A Smaller Number Plate For My Vehicle…?

You can definitely mount smaller number plates to your vehicle so long as the; Character height, Character width, Character stroke, spacing and margins all comply with the legislative requirements set out in the aforementioned Regulations regarding the vehicle the smaller number plate is to be mounted to. We do have further information on smaller number plates here and we do have the facilities to accommodate any size number plate (within reason)! The overall size of the number plate is therefore subject to the number of characters and how many 1’s or I’s are within the registration. As 1’s and I’s are narrower than the other characters, number plates can legally be shortened by the difference in width; 34mm narrower on imported vehicles and 36mm narrower on UK spec vehicles.

When considering the height of a number plate and particularly for a square plate (a number plate with 2 rows of characters), the smallest dimensions for height are as calculated above. Legally, number plates can be any reasonable size so long as they do not fall below the legal minimum specifications.

Here at JDM Plates we, can definitely help if you are you interested in some smaller imported size number plates or smaller number plates for your UK spec vehicle; fully legal. We offer a range of styles and within these listing we offer a range of sizes; please visit our Number Plates & Accessories Page for the full range of our products! All of our smaller imported number plates come with a declaration of legality to prove they’re legal too.

If you have a motorcycle and would like some smaller motorcycle number plates then please visit our article HERE.

We offer the smallest legal imported number plates in the country for all vehicles including motorcycles and offer documentation to prove legality. We offer a range of 4D variants such as:-

Imported 4D 3mm

Imported 4D 5mm

UK Spec 4D 3mm

UK Spec 4D 5mm

For all number plate enquires, please feel to leave us a message using the contact forms scattered around the website. Alternatively, please call us on 01493 230023.

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