Lens Equation Calculator
Focal length, image distance and magnification.
Enter your values
ⓘ Live results
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
- 1Enter the lens focal length.
- 2Enter the object distance from the lens.
- 3Read image distance and magnification.
Worked example
Using the values the calculator loads with:
Inputs
- Focal length50 mm
- Object distance1500 mm
Results
- Image distance51.72 mm
- Magnification0.0345×
- Image typeReal and inverted
- Field ratio1:29
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.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.