Eye Prescription Calculator: Convert Your Eyeglass Rx Online

Use this tool to calculate your eye prescription needs quickly and accurately.

Eye Prescription Calculator

How to Use the Calculator

Enter your eye prescription information into the respective fields. Use the following guidelines:

  • Sphere (SPH): This value corrects nearsighted or farsighted vision.
  • Cylinder (CYL): This value corrects astigmatism if present. Leave blank if not applicable.
  • Axis: This number describes the lens meridian that contains no cylinder power, measured in degrees from 0 to 180. Leave blank if not applicable.
  • Addition (ADD): This is the added magnifying power applied to the bottom part of multifocal lenses, to correct presbyopia.

After entering your information, click the “Calculate” button to see your results.

How It Calculates the Results

The calculator takes the values of SPH, CYL, AXIS, and ADD and outputs them directly in this example. A real prescription calculator would use these values to determine the correct lens power needed for glasses or contact lenses.

Limitations of the Calculator

This calculator is a simplified tool designed for demonstration purposes. It does not replace a professional eye exam and should not be used for ordering corrective lenses without validation from an eye care professional.

Other Resources and Tools