There’s no single “legal number plate size” in UK law. Instead, the law fixes the size of the characters, spacing and margins – and the plate has to be big enough to hold them. That’s why you’ll find several standard sizes, plus “cut to fit” plates for cars with unusual recesses.
In this guide
The common sizes, drawn to scale
| Plate | Size (mm) | Size (inches) | Lines | Typical use |
|---|---|---|---|---|
| Standard car | 520 × 111 | 20.5 × 4.4 | 1 | Most cars, front and rear |
| Large rear | 533 × 152 | 21 × 6 | 1 | Range Rover, Land Rover, some US vehicles |
| 4×4 square | 279 × 203 | 11 × 8 | 2 | Square rear recesses on SUVs and 4x4s |
| Motorcycle | 229 × 178 | 9 × 7 | 2 | Motorcycles registered from 1 Sept 2001 |
| Import | 330 × 165 / 330 × 178 | 13 × 6.5 / 13 × 7 | 2 | Japanese and other imports |
| Short legal | Cut to fit × 111 | – | 1 | Short registrations and small recesses |
| Hex | Cut to fit × 111 | – | 1 | Angled ends for supercar-style looks |
What decides whether a size is legal
For a car plate, every size must fit:
- characters 79mm tall and 50mm wide (1 and I are narrower)
- 11mm between characters and 33mm between the two groups
- 11mm clear margins top, bottom and sides
- room for any flag or identifier without touching those margins
On two-line plates, the gap between the lines is 19mm. Motorcycle characters are smaller (64mm), which is why bike plates are compact. Full measurements are in our number plate law guide.
Standard car plates: 520 × 111mm
The default for the vast majority of UK cars, front and rear. It fits any seven-character registration plus a badge with room to spare.
Square 4×4 plates: 279 × 203mm
Many SUVs, 4x4s and some hatchbacks have a square recess at the rear. A two-line plate puts the first group on the top line and the second on the bottom. Legal-size characters fit comfortably.
Motorcycle plates: 229 × 178mm (9 × 7″)
Motorcycles registered from 1 September 2001 must show a rear plate only, on two lines, with 64mm characters. Smaller 8 × 6″ and 7 × 5″ plates are popular but can’t fit legal characters for most registrations – they’re show-only. Details in motorcycle number plate rules.
Import plates: 330 × 165mm and 330 × 178mm
Japanese and some US imports often have a near-square recess. The rules allow smaller 64mm characters on imported vehicles whose plate space wasn’t designed for a standard UK plate. See number plates for imported cars.
Short and hex plates
Short registrations (like “R9 LLY”) don’t need a full 520mm plate. A short legal plate keeps every legal measurement but trims the spare plate away. Hex plates add angled ends. Both are explained in are short and hex plates legal?
How to measure your car
- Measure the width and height of the recess or mounting area, not your old plate.
- Note any curves, sensors or cameras near the plate.
- Check whether your rear recess is rectangular or square.
- If in doubt, choose a standard size – plates can be trimmed slightly at the edges but not enlarged.
In the plate builder you can pick different sizes for the front and rear, or enter a custom size. The builder will tell you instantly if your registration fits legally.
Frequently asked questions
What size is a UK number plate?
The standard car plate is 520mm × 111mm, but other sizes are legal as long as the characters, spacing and margins fit.
Can I have a smaller number plate?
Yes, if it still fits 79mm characters with correct spacing and 11mm margins. You can’t shrink the characters on a car.
What size is a square number plate?
The common square size is 279mm × 203mm (11 × 8 inches), with the registration on two lines.
What size is a motorcycle plate?
The standard is 229mm × 178mm (9 × 7 inches) with two lines of 64mm characters.
