In short
- Post-2001 car and full-size plates use 11 mm character gaps and a 33 mm gap between registration groups.
- Motorcycle and motor tricycle plates from 1973 onward use smaller characters, a 30 mm group gap and two lines.
- A typed checker can confirm grouping but cannot certify the manufacture of a physical plate.
There is one prescribed gap inside each registration group and a larger gap between the groups. The live check below can spot a misplaced typed space. The measurements show what a compliant manufacturer has to reproduce on the physical plate.
How should a UK registration be spaced?
Keep the assigned characters in their prescribed groups. A current registration is shown as GM26 SNP, a prefix registration as A123 BCD and a suffix registration as ABC 123A. Do not move or close the group space to suggest a word.
This recognises those three dated GB formats. It deliberately refuses dateless, Northern Irish and unusual personalised marks rather than guessing where a physical gap belongs. The UK number plate formats guide explains how those other schemes differ.
What are the legal car number plate measurements?
Post-2001 car and full-size plate characters are 79 mm high and normally 50 mm wide, with a 14 mm stroke. The gap between characters is 11 mm, the gap between groups is 33 mm and the minimum top, bottom and side margin is 11 mm.
| Measurement | Required dimension |
|---|---|
| Character height | 79 mm |
| Character width | 50 mm, except 1 and I |
| Stroke width | 14 mm |
| Between characters | 11 mm |
| Between groups | 33 mm |
| Minimum margin | 11 mm |
| Between vertical lines | 19 mm |
The group gap is not a keyboard-space setting. It is the clear physical distance between the two prescribed groups. If a full-size registration is displayed over two lines, the published vertical line gap is 19 mm.
What spacing does a motorcycle number plate use?
For motorcycles and motor tricycles registered from 1 January 1973, characters are 64 mm high and normally 44 mm wide, with a 10 mm stroke. Character gaps are 10 mm, the group gap is 30 mm, the minimum margin is 11 mm and the gap between the two lines is 13 mm.
| Measurement | Required dimension |
|---|---|
| Character height | 64 mm |
| Character width | 44 mm, except 1 and I |
| Stroke width | 10 mm |
| Between characters | 10 mm |
| Between groups | 30 mm |
| Minimum margin | 11 mm |
| Between vertical lines | 13 mm |
Motorcycles registered on or after 1 September 2001 may display only a rear plate, and that registration must be arranged over two lines. A three-line motorcycle plate is not permitted under the current GOV.UK display guidance.
What else makes a UK number plate compliant?
Spacing alone is not enough. The plate also needs the prescribed typeface and colours, reflective material, the plate supplier’s details and the applicable British Standard mark. Its background must not carry a pattern.
GOV.UK says the front plate displays black characters on white and the rear displays black characters on yellow. Plates made after 1 September 2021 must meet BS AU 145e, and their characters must be a single shade of black. The characters must not be removable or reflective.
Rearranging or altering the characters can lead to an MOT failure and a fine of up to £1,000. That is why a show plate or a visually clever personalised arrangement is not evidence that the plate is legal for road use.
Can this checker certify a physical number plate?
No. It checks the typed grouping for three common dated GB formats and prints the official measurements. Only inspection of the manufactured plate can establish its physical gaps, character shape, materials, markings and condition.
The measurements come from the official DVLA INF104 publication. The current colour, material, marking and motorcycle requirements are on GOV.UK’s number plate rules. The underlying dimensions are also set out in the Road Vehicles regulations. Use the plate year chart if the age character is the part you need to identify.
Questions people actually ask
- What is the legal gap between characters on a UK car number plate?
- For car and full-size plates using the post-2001 character rules, the gap between characters is 11 mm. The larger gap between the two registration groups is 33 mm, and the minimum margin around the registration is 11 mm.
- Can I change number plate spacing to make a word?
- No. GOV.UK says characters must not be rearranged or altered so the registration is hard to read. A personalised mark still has to use its assigned characters and prescribed grouping rather than closing or moving spaces to suggest another word.
- Are motorcycle number plate character sizes different?
- Yes. For motorcycles and motor tricycles registered from 1 January 1973, characters are 64 mm high and normally 44 mm wide, with a 10 mm stroke and character gap. Their group gap is 30 mm, minimum margin is 11 mm and line gap is 13 mm.
- Can an online checker prove that a number plate is legal?
- No. It can compare typed grouping with a recognised registration format and show the published measurements. It cannot measure a physical plate or verify its typeface, reflective material, colour, supplier details, British Standard mark, construction or condition.
Written by Jonathan in Derby. Last updated .