Online Vision Acuity Test
A printable Snellen style eye chart you can read from your screen at home.
Runs entirely in your browser. This is a screening aid, not a clinical exam, and no data leaves your device.
How to use this tool
Set the distance you will sit from your screen, then build the chart. Cover one eye, read down the chart until the letters become hard to make out, and note the smallest line you can read clearly. Repeat with the other eye. The label beside each line is its approximate Snellen score at the chosen distance.
How it works
A real eye chart sizes each letter so that the smallest readable line corresponds to a standard acuity score. Screen sizes and pixel densities vary, so the lines here are approximate. The result is a rough screening rather than a measured prescription.
A real example
Sitting 10 feet from the screen, you can read every line clearly down to the line labeled 20/30 but the 20/20 line is blurry. That suggests your distance vision in that eye is around 20/30, which is a reason to book a proper eye exam.
Common questions
Can this replace an eye exam?
No. It is a screening aid only. Screen sizes differ and it cannot check for many eye conditions. See an optometrist for a real exam and any prescription.
Why does distance matter?
Acuity is defined at a set distance. The further you sit, the harder small letters are to read, so the chart adjusts the labels to the distance you enter.
Should I wear my glasses?
Test both ways if you like. Wearing your usual correction checks whether your current glasses still work well, while testing without it screens your uncorrected vision.
Is my data sent anywhere?
No. The chart is generated entirely in your browser and nothing you do here is uploaded or stored on a server.