Optical Calculators

We're here to help you exceed the standard of care, right? Well, we use these calculators every day here at Chadwick Optical. Rather than hoard them in our own private Excel spreadsheets, we thought it would be useful to share them with the world. So here they are. Free, no strings, no login required.

We've split them into two groups: general opticianry calculators that cover the calculations most practitioners reach for regularly, and low vision calculators built for more specialized work: magnification, field of view, equivalent power, and so on.

Note for non-US users: These calculators rely on US lens processing and index of refraction conventions, which differ from international standards.