4D number plates – plates with laser-cut acrylic characters that stand proud of the plate – are one of the most popular upgrades for UK drivers. They're also one of the most misunderstood. Search online and you'll find people saying they're banned, and others selling them with no mention of the rules at all.
The short answer: 4D number plates can be road legal in the UK, as long as they meet the same rules as any other number plate. The style of the characters isn't what makes a plate legal or illegal – the font, size, spacing, colours and the standard it's made to are.
What changed in 2021
On 1 September 2021 the British Standard for number plates was updated to BS AU 145e. Two changes matter for 4D plates:
- Raised characters are allowed, but only in a single colour. Characters must be black. The old trend of two-tone or shaded 3D effects – for example black characters with a grey or coloured edge – is no longer permitted.
- Plates must be more durable. New plates have to meet tougher tests for weather resistance, abrasion and impact, and must be marked with the supplier's name and postcode and the BS AU 145e standard.
Laser-cut black acrylic characters fit within those rules. Coloured, chrome or two-tone 4D characters do not.
The rules every 4D plate still has to follow
A 4D plate is still a number plate, so everything in the DVLA's display rules applies:
- The correct font. Characters must use the prescribed "Charles Wright" style typeface. No italic, script or stylised fonts.
- The correct size. Each character must be 79mm tall and 50mm wide (except the number 1 and the letter I), with a 14mm stroke.
- The correct spacing. 11mm between characters, 33mm between the two groups, and at least 11mm of margin around the edges.
- The correct colours. Black characters on a white reflective background at the front, and on a yellow reflective background at the rear.
- No re-spacing. You can't move characters closer together or further apart to make them spell a word or name.
If a 4D plate meets those rules, is made to BS AU 145e and is supplied by a DVLA-registered supplier who has checked your documents, it's a road-legal plate.
3mm or 5mm – does the depth matter?
There's no rule that sets a maximum depth for raised characters, and both 3mm and 5mm 4D characters are common. The difference is purely visual:
- 3mm gives a clean, subtle raised look that suits most cars.
- 5mm casts deeper shadows and has more presence, especially on larger vehicles.
You can compare both side by side in our number plate builder, which renders the characters at their true depth.
When a 4D plate is not road legal
A 4D plate becomes a show plate – not for use on the road – if:
- the characters are coloured, chrome, or two-tone
- the font isn't the prescribed style, or the characters have been shrunk to fit a short plate
- the spacing has been changed
- it isn't made to BS AU 145e or doesn't carry the supplier and standard markings
Show plates are fine for shows and display, but displaying one on the road can lead to a fine of up to £1,000 and an MOT failure.
How to get road-legal 4D plates
When you order through Rogue Automotive, our builder checks the layout as you design – character size, spacing and margins – and clearly labels any design that can only be a show plate. For road-legal plates we'll ask for proof of your entitlement to the registration and your ID at checkout, as the law requires.
Ready to see yours? Build your 4D plates in 3D, or read more about 4D number plates and our road legal guide.