Test Your Eyesight Online, One Eye at a Time
Calibrate your screen with a credit card, stand 3 meters (10 feet) away and point out which way the E faces: you get an acuity estimate for each eye, in Snellen (20/20) and /10 notation. A rough screening that doesn't replace an eye exam with a professional.
- Tumbling E chart
- 20/20 and /10 results
- Astigmatism and contrast
- Rough screening
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How to take an online eye test
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Calibrate your screen
Adjust the rectangle on screen to the size of a credit card (85.6 mm / 3.37 in long) held against the screen: the letters will then be shown at their real size.
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Step back
Move back 3 meters (or 2 m, 1 m or 40 cm if needed) and cover one eye with your hand without pressing, wearing your usual glasses or contacts if you have them.
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Point out which way the E faces
Answer with the arrows: the E gets smaller until you make a mistake, then you switch to the other eye. The result is shown in /10 and as a Snellen equivalent.
Three vision tests on a single screen
Acuity for each eye
The E in 4 orientations, smaller and smaller: result in tenths on the Monoyer scale (for example 8/10) and as a Snellen equivalent (20/25).
Calibrated real size
Calibrating with a credit card gives the letters the right size, whatever your screen and its resolution.
Astigmatism test
A dial of lines: if some look darker or sharper than others, talk to an eye care professional.
Contrast sensitivity
A separate test that checks how faint a contrast you can still make out shapes at, an ability that's different from acuity.
Understanding your result: 20/20, 6/6, 10/10
In the US, visual acuity is written in Snellen notation: 20/20 is considered normal vision, and some people even do better. The UK and many other countries use the metric version, where 6/6 means the same thing. France uses tenths on the Monoyer scale, which this tool also shows: 10/10 equals 20/20 and 6/6, 8/10 equals about 20/25 and 5/10 equals 20/40. At 20/20, the smallest E you read spans an angle of 5 minutes of arc, or about 4.4 mm tall at 3 meters. A result of 20/25 (8/10) means you need letters 1.25 times bigger to read them. The test is done one eye after the other, because a good eye can hide a weaker one when you look with both. A clear difference between your two eyes is worth getting checked.
Why calibrate your screen and stick to the distance
An on-screen eye test only makes sense if the letters are shown at their exact real size. But the same number of pixels doesn't take up the same space on a phone, a laptop or a large monitor. That's why the tool first has you match a rectangle to the size of a credit card, a standard format 85.6 mm long. Distance matters just as much: standing 2 meters away when the test is set for 3 meters skews the result. At short distances, the small letters become tiny: at 40 cm, a 20/20 E is only about 0.6 mm tall, just a few pixels, which makes the measurement less reliable. So go for 3 meters, in a well-lit room, with a bright enough screen and no glare.
What this test doesn't replace
This test gives an estimate of your acuity and can tell you it's time for a checkup, but it isn't an eye exam. It doesn't measure your prescription in diopters, can't be used to get glasses or contact lenses, and doesn't detect glaucoma, cataracts or retinal disease, which can progress for a long time without symptoms. To have your vision measured and your eye health checked, see an optometrist or an ophthalmologist. Get care right away for sudden vision loss, eye pain, flashes of light, a curtain over your vision or double vision. Also book an appointment if your result is low, if your two eyes differ clearly, if reading gives you headaches or if your last checkup was several years ago.
Frequently Asked Questions
How can I test my eyesight online?
Calibrate your screen with a credit card, stand 3 meters (10 feet) away, cover one eye and point out which way the E faces until you make a mistake, then repeat with the other eye. The result is an estimate, not a diagnosis.
Are online eye tests accurate?
They give a useful indication if the screen is properly calibrated, the distance is right and the room is well lit. They don't replace an exam with an optometrist or ophthalmologist, who measure your vision precisely and check the health of your eyes.
What does 20/20 vision mean?
It's the acuity considered normal: at 20 feet, you can make out details that a person with normal vision sees at 20 feet. It equals 6/6 in metric notation and 10/10 on the French Monoyer scale.
How do I know if I have astigmatism?
Look at the dial of lines, one eye at a time: if some lines look darker, sharper or thicker than others, it may point to astigmatism. Only an eye exam can confirm and correct it.
What vision do you need to drive?
It depends on the country. In France, a standard car license requires at least 5/10 (about 20/40) with both eyes open, with glasses or contacts if needed; many countries use a similar threshold, such as 6/12 in the UK. An online test doesn't count as proof: if in doubt, have your eyes checked by a professional.