Science

Lens Equation Calculator

Focal length, image distance and magnification.

Enter your values

Results update instantly as you type — no submit needed.

Results
Image distance
51.72 mm
Magnification
0.0345×
Image type
Real and inverted
Field ratio
1:29

Quick answer

The thin lens equation links object distance, image distance and focal length.

1/f = 1/do + 1/di

How to use the Lens Equation Calculator

  1. 1Enter the lens focal length.
  2. 2Enter the object distance from the lens.
  3. 3Read image distance and magnification.

Frequently asked questions

What is 1:1 macro?

Magnification of 1, when object and image distances both equal 2f.

Why is magnification negative?

The sign convention marks an inverted real image.