Eye Test Chart
A Snellen and a Tumbling E chart drawn at true angular size for your screen, after a one-step calibration with a credit card. Walk the lines one at a time and get an approximate visual acuity reading.
A screen test is a screening aid, not an eye test. It cannot measure refraction, eye health, astigmatism or contrast sensitivity, screen glare and room lighting change the result, and it cannot replace a qualified optometrist or ophthalmologist. If you notice a change in your vision, book a proper examination.
1. Calibrate your screen
Hold a real credit or bank card against the screen and drag the edge of the grey card below until they are exactly the same width. This sets how many pixels make a millimetre, which is what makes the letters the right size.
2. Set the test up
Measure it. A metre out changes the letter sizes by 30%.
The full chart
Every line at true size for 3.00 m, on a white background so contrast stays high. Cover one eye and read downwards to find your smallest legible line.
Snellen notation 20/20 means the letter subtends 5 minutes of arc at the stated distance. Every size here is derived from that definition using your calibration, so no two screens should disagree once both are calibrated.
About this tool
The chart scales optotypes with the classic Snellen definition: a 20/20 letter subtends five arcminutes of visual angle, so its cap height in millimetres is fixed by the viewing distance you enter. Letters are drawn as pixel-perfect bitmaps rather than text, because font rendering would round the size and break the measurement. Calibration, the distance and the answers stay in your browser — nothing is uploaded.
- 100% free — no account needed
- Runs in your browser
- Nothing is uploaded
Frequently asked questions
Is Eye Test Chart really free?
Yes. Eye Test Chart is completely free on PureBrowser — every feature, with no account, no trial, and no credit card.
Does Eye Test Chart upload my data?
No. Eye Test Chart runs entirely inside your browser, so anything you type, paste, or open stays on your own device.
Do I need to sign up or install anything?
Neither. There is no account and nothing to download — open the page and Eye Test Chart is ready to use on desktop or mobile.
Does Eye Test Chart work offline?
Once the page has loaded, yes. All of the processing happens locally in your browser, so it keeps working without a connection.
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