Reading-glasses strength estimator
A calibrated arm's-length test and a few quick questions → a diopter range to skip the “+2.00 drugstore grab.” An estimator, not a prescription.
How the estimator works
Test + your age
A calibrated arm's-length test plus a few short questions.
AAO age table
Rule-based mapping calibrated to the AAO presbyopia table.
Your estimate
A diopter range to shop off-the-shelf readers with.
What this tool helps with
Picking off-the-shelf reader strength
OTC readers come in fixed 0.25 D steps. We narrow the right step.
Preventing the +2.00 grab
most first-time buyers reach for too strong a reader and end up with another pair on a shelf.
Identifying when readers aren't the answer
if you have distance Rx or progressives, this tool routes you to an eye exam instead.
A printable diopter chart
to bring to your next eye exam (delivered by email).
An estimator, not a prescription
We map your answers through a rule-based table calibrated against the AAO Refractive Errors Preferred Practice Pattern. We can estimate a reasonable diopter range — but real prescriptions account for astigmatism, vergence, and binocular balance that self-reported answers can't measure. The AOA recommends a comprehensive eye exam every two years after age 40.
Read the full methodology for the rules behind the estimate.