Calculate lens power from focal length or object/image distances.
Optical Parameters
cm
- OR -
D
Calculation Results
Enter focal length or power
About this calculator
Quick Reference
PLens Power
fFocal Length
Positive (+)Converging lens
Negative (-)Diverging lens
Overview
A diopter (D) is a unit of measurement for the optical power of a lens or curved mirror. It is equal to the reciprocal of the focal length measured in meters.
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Pro Tips
A positive diopter (e.g., +2.0 D) indicates a converging lens (used for farsightedness).
A negative diopter (e.g., -2.0 D) indicates a diverging lens (used for nearsightedness).
Reading glasses typically range from +1.00 to +3.00 diopters.
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Fun Facts
"The term 'diopter' was proposed by French ophthalmologist Ferdinand Monoyer in 1872."
"The human eye has an optical power of about 60 diopters when relaxed."
