Custom number plates: what you can and can't change
Buying Guide · 1 October 2026 · 4 min read
More choice than most people think, within a few fixed rules. A guide to customising a plate and keeping it legal.
What you can customise on a road-legal plate
| Option | Choices |
|---|---|
| Letter style | Printed, 3D gel, 4D acrylic (3 mm or 5 mm), 4D gel |
| Size | Standard, short, hex, 21 x 6 and more |
| Border | On or off |
| Flag | Union flag, Saint George, Saltire, Red Dragon, or none |
| Green flash | Zero-emission vehicles only |
What stays fixed
- The Charles Wright font
- Character size and spacing
- White front, yellow rear, reflective
- Supplier name and BS AU 145e mark
See number plate spacing rules for the exact measurements.
Show plates open up more
Slogans, different fonts, tints and custom badges are all allowed on a show plate. Just keep it off the road.
Design yours
The plate builder shows a live 3D preview so you can see each option before you buy. Need help choosing? Read choosing number plates for your car colour.