Here at Chadwick Optical, we use these calculators every day. Rather than hoard them in our own private Excel spreadsheets, we thought it would useful to share them with the world! P.S. The world may not find them very useful. When processing lenses in the US, we make some assumptions about index of refraction that seem crazy to the rest of the world.


Converts plus to minus cylinder form to easily transpose any prescription. 

Measure and find the conversion of diopter measurements to radius of curvature.
Calculate the correct base curve/thickness magnification by manipulating transcription manufacturing.
See how the power of the prescription changes based on the lens distance to your eye.
Use the curve in diopters to calculate the sagitta of an arc.