🔍 Magnification of a Lens Calculator
Enter the object distance and focal length to find the image distance and magnification of a thin lens.
cm
cm
The thin lens formula
This calculator uses the thin lens equation, 1/f = 1/do + 1/di, rearranged to solve for image distance: di = (f × do) / (do − f). Magnification is then m = −di / do.
A negative magnification means the image is inverted relative to the object; a magnitude greater than 1 means the image is larger than the object. This model assumes an ideal thin lens and is intended for general educational and planning purposes.
Last reviewed August 2026