The number plate test
The everyday legal standard for driving a car is straightforward: you must be able to read a current-style car number plate, in good daylight, from 20 metres away, wearing glasses or contact lenses if you normally use them. That is roughly the length of five parked cars. If you cannot read a plate at that distance, you must not drive, and you should have your eyes tested.
This single test is the one the police can ask you to perform at the roadside, and failing it can mean prosecution, so it is worth checking yourself from time to time.
The visual standards behind the test
Behind the number plate test sit two medical standards. The first is sharpness of vision (visual acuity): for a car you must meet at least the standard of 6/12 on the optician's chart with both eyes open, with any glasses or lenses you wear. The second is your field of vision, the width of what you can see around you while looking straight ahead, which must be wide enough and free of significant gaps. You can explore how these are measured with the vision standards tool.
Most people who pass the number plate test also meet these standards comfortably. They become relevant mainly when an eye condition affects either the sharpness or the field of your vision.
Conditions you must report
You are legally required to tell the DVLA about certain eye conditions, even if you feel you can see well. These include sight in only one eye in some circumstances, double vision, and any condition affecting both eyes that reduces your field of vision, such as glaucoma, or the effects of a stroke. Conditions affecting just one eye are often acceptable for car driving if the other eye meets the standard, but the rules differ for lorries and buses.
If you are unsure whether a condition needs reporting, the safe course is to check on GOV.UK or ask your optometrist or ophthalmologist. Not reporting a notifiable condition is an offence.
If you don't meet the standard
If you cannot meet the eyesight standard, you must not drive. Sometimes the answer is simple, such as an up-to-date pair of glasses that restores your vision to the required level. Where a condition has reduced your sight or your field of vision more permanently, the DVLA will assess whether you can continue to drive, often with the help of a formal visual field test arranged through an optometrist or eye clinic.
The most important thing is not to keep driving while unsure. Have your eyes tested, find out where you stand, and let the DVLA make the formal decision where one is needed.
Not sure if you meet the standard?
Try the vision standards tool →Common questions
How far must I be able to see to drive?
You must be able to read a current-style car number plate from 20 metres, wearing glasses or contact lenses if you normally use them. That is about the length of five cars parked end to end.
What eyesight do I legally need to drive a car?
In addition to the number plate test, you must meet a visual acuity standard of at least 6/12 with both eyes open and have an adequate field of vision. Glasses or contact lenses count, so wear them if you need them.
Do I have to tell the DVLA about my eyes?
You must report certain conditions, including reduced field of vision, double vision, and some cases of sight in only one eye. Many one-eyed drivers can still drive a car if the other eye meets the standard, but you should check the current rules on GOV.UK.
Can I drive with sight in only one eye?
Often yes for a car, provided your remaining eye meets the acuity and field standards and you have adapted. You may need to notify the DVLA. The standards are stricter for lorries and buses. Always confirm with GOV.UK or your eye specialist.
What is 6/12 vision?
It is a measure of sharpness on the optician's chart. Roughly, it means you can see at 6 metres what a person with standard vision sees at 12 metres. It is the minimum sharpness required to drive a car in the UK.
This page explains the standards in general terms and is not legal advice. The DVLA sets and updates the rules, so always check the current requirements on GOV.UK. If you are unsure whether you meet the standard, have your eyes tested by an optometrist or ophthalmologist. Last reviewed May 2026 by Chris Matthews, Consultant Ophthalmologist.
