🔍 Thin Lens Equation Calculator
Use the thin lens equation to find where an image forms and how large it appears for a converging or diverging lens.
What the thin lens equation tells you
The thin lens equation, 1/f = 1/do + 1/di, connects a lens’s focal length (f) to the object distance (do) and image distance (di). It works for both converging (convex) and diverging (concave) lenses under the standard thin-lens sign convention.
How this calculator works
Enter the focal length and object distance in the same units. The calculator solves for image distance and then finds magnification using m = -di/do. A positive image distance indicates a real image on the opposite side of the lens from the object; a negative value indicates a virtual image on the same side as the object.
Use a positive focal length for converging lenses and a negative focal length for diverging lenses. This tool is for general physics education and planning purposes, not a substitute for precise optical design software.