Diopter indicates the amount of curvature of a lens. The thicker the lens, the bigger the curvature.

To find the approximate magnification level of a lens, divide its diopter by 4, and add 1.

The equation is:

Magnification = Diopter ÷ 4 + 1

For example:

For a 3-diopter lens of a magnifier, its magnification = 3/4 + 1 or 0.75 + 1 = 1.75x. Objects viewed under a 3 diopter lens will appear 1.75X larger than normal.

For a 5-diopter lens of a magnifier, its magnification = 5/4 + 1 or 1.25 + 1 = 2.25x. Objects viewed under a 5 diopter lens will appear 2.25X larger than normal.

For a 8-diopter lens of a magnifier, its magnification = 8/4 + 1 or 2 + 1 = 3x. Objects viewed under a 8 diopter lens will appear 3X larger than normal.

Use this chart to convert diopters to magnification simply.

Diopter to Magnification