UK number plates look simple, but there's a surprising amount of detail behind them. This guide covers every rule that decides whether a plate is road legal – so you can buy with confidence and avoid a fine.
The font
All UK plates must use the prescribed "Charles Wright" style typeface. Italic, script, bold-stylised and novelty fonts aren't allowed – even if they're still easy to read.
Character size and spacing
- Characters are 79mm tall and 50mm wide (except 1 and I).
- Every stroke is 14mm thick.
- 11mm between characters, 33mm between the two groups.
- At least 11mm of clear margin at the top, bottom and sides.
- On two-line plates, 19mm between the lines.
You can't change the spacing to make a registration spell a word – for example, moving "S" and "AM" together to read "SAM". Doing so is illegal and can lead to the registration being withdrawn.
Colours
- Front: black characters on a white reflective background.
- Rear: black characters on a yellow reflective background.
- No background patterns and no reflective borders.
Raised characters
3D gel and 4D characters are allowed, but since September 2021 they must be a single colour – black. Two-tone or coloured effects aren't permitted on road plates. See are 4D number plates legal?
Borders
A non-reflective border is allowed around the edge of the plate. It mustn't intrude into the margins around the characters.
National flags and identifiers
You can display the UK national identifier on the left of the plate, with or without the Union flag. Since September 2021 "GB" is no longer valid when driving abroad, so the UK identifier is the one to choose if you plan to travel.
The BS AU 145e standard
Plates made since 1 September 2021 must meet BS AU 145e. That means:
- tougher durability standards (weather, abrasion, impact)
- the supplier's name and postcode marked on the plate
- the standard's code, "BS AU 145e", marked on the plate
Who can make road-legal plates
Only suppliers registered with the DVLA's Register of Number Plate Suppliers can make road-legal plates, and they must see your proof of entitlement and ID.
The penalties
Driving with an incorrectly displayed plate can lead to a fine of up to £1,000, an MOT failure, and the DVLA can withdraw a personalised registration that's been misrepresented.
Checking your plates before you order
Our number plate builder checks the font size, spacing and margins as you design and clearly labels any design that can only be a show plate. For a full summary, see our road legal guide.