The angle a printed grid covers
When an Amsler grid is printed on paper, the same sheet subtends a smaller angle the further away it sits. Enter the side length of the printout, the distance from your eye to the paper, and the number of cells along one side, and the page returns the angle the grid covers, the center-to-edge angle, the average angle per cell and the physical size of a single cell.
The formula is angle = 2 × arctan((side ÷ 2) ÷ distance), converted to degrees (as of October 2026). The per-cell figure is the total divided by the number of cells, so read it as an average: edge cells subtend slightly less than central ones. The formula used is printed in the results so you can see which one produced the number.
The standard grid is 4 in (10 cm) with 20 squares a side, and at about 14 in each square spans about 1 degree (StatPearls). Lines that look wavy, broken or missing are treated as findings for an eye exam; there is no numeric cutoff for how many squares count as abnormal. This page gives no risk score, because a score built on unpublished weights would reassure people whose result comes out low and delay the care they need. Macular degeneration is identified by an eye examination, and checking at home does not stand in for it. New distortion or a new blank spot in central vision is a reason to see an eye doctor without delay.
Frequently asked questions
A standard Amsler grid is 4 in (10 cm) square with 20 squares a side (0.2 in, 5 mm each); viewed from about 14 in (33 cm), each square spans roughly 1 degree of visual field (StatPearls). Wear your usual reading glasses, cover one eye at a time and look at the center dot. If your eye doctor gave you different settings, enter those to check the angle.
There is no basis for screening for macular degeneration at home without a dilated eye examination. A score built on weights nobody has published would let a low result reassure someone into delaying care. So the page does arithmetic and stops there.
New distortion or a new blank patch in your central vision is a reason to see an eye doctor without delay. Seeing nothing unusual, on the other hand, does not mean nothing is wrong; the examination is what settles it.