What Are 4D Number Plates? 3mm, 6mm and Gel Explained

Short answer: what are 4D number plates? They’re plates where each character is laser-cut from solid black acrylic, usually 3mm or 6mm thick, and bonded onto a reflective plate. The letters stand up with sharp, square edges and cast a real shadow, so they look almost engraved. They’re road legal in the UK when made to BS AU 145e.

The “4D” name is marketing. There’s no fourth dimension. It’s there to separate laser-cut letters from 3D gel, where the letters are printed and covered in a rounded gel dome.

Written by the PlateBoss team, a DVLA-registered number plate supplier with a workshop in Hounslow, west London. Updated and checked against DVLA and GOV.UK guidance, September 2026.

In this guide

• How 4D plates are made
• 3mm vs 6mm
• Types of 4D plate
• Are 4D number plates legal?
• Pros and cons
• Prices
• FAQs

How 4D number plates are made

1. The registration is set out in the Charles Wright font at the legal size and spacing.
2. A laser cuts each character from a sheet of black acrylic, which gives perfectly square, clean edges.
3. The letters are bonded to a reflective acrylic plate, white for the front and yellow for the back.
4. The supplier’s name, postcode and the BS AU 145e mark are added, and the plate is checked before it goes out.

3mm vs 6mm 4D plates

3mm is the subtle option. The letters are raised just enough to catch the light, and it looks tidy on almost any car. 6mm doubles the depth, so the shadow is much stronger and the plate stands out from further away. On sporty or larger cars, most of our customers go 6mm.

Types of 4D number plate

• 4D (3mm or 6mm): laser-cut letters with a matt or satin black finish.
• 4D gel: laser-cut letters with a clear gel dome on top for extra gloss.
• 4D retro: 4D letters on a bevelled-edge plate for a classic look.

Are 4D number plates legal?

Yes. Since September 2021, GOV.UK says plates can have raised characters, as long as they’re a single shade of black, in the legal font and size, and the plate carries the supplier’s details and the BS AU 145e mark. A 4D plate with two-tone or coloured letters, a stylised font or squashed spacing isn’t legal. We’ve covered it in full in are 4D plates legal?

You’ll also need to show your ID and V5C, like with any road-legal plate. Here are the documents needed for number plates.

Pros and cons of 4D number plates

Pros: the sharpest, most premium look; letters won’t go cloudy or yellow; they keep their shape for years; they come in two depths.

Cons: a hard, sharp knock can chip an edge; 6mm costs more than 3D gel; and it’s a bolder look that doesn’t suit every car.

Not sure if 4D is right for you? Compare it with gel in 3D vs 4D number plates.

What do 4D number plates cost?

At PlateBoss: 4D 3mm £49.99, 4D 6mm £64.99, 4D gel from £64.99, and 4D retro £69.99, all for a pair with free tracked delivery. Order before 2pm for same-day dispatch, or collect from our Hounslow workshop.

4D number plates

-29%

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4D 3mm Number Plates

Rated 5.00 out of 5

£70.00 Original price was: £70.00.£49.99Current price is: £49.99.

-28%

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4d 6mm Number Plates

£90.00 Original price was: £90.00.£64.99Current price is: £64.99.

-28%

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Buy 4d gel 3mm Number Plates

Rated 5.00 out of 5

£90.00 Original price was: £90.00.£64.99Current price is: £64.99.

-36%

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4d Retro Number Plates

£110.00 Original price was: £110.00.£69.99Current price is: £69.99.

What are 4D number plates? FAQs

Sources

• GOV.UK: Rules for number plates