Physics

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Thin Lens Equation Calculator.

Calculate image distance and magnification for a Gaussian thin lens.

On-device calculationNo signup
01

Set your values

Results update as you type.

Image distance: 0.066667 m

Image distance

0.000000m
Magnification: -0.333333 ×

Magnification

0.000000×

Results update automatically as you type.

Use Cases

Optics Lab Calculations

Quickly determine where an image will form and its magnification for a given lens and object position, aiding in experimental setup and verification.

Example: For a lens with f=0.2 m and object distance 0.5 m, find image distance and magnification.

Lens Design and Education

Use as a teaching tool to explore how changing focal length or object distance affects image properties, reinforcing the thin lens equation.

Example: Compare image distance for object distances of 0.3 m and 0.6 m with f=0.1 m.

Frequently Asked Questions

How do I use the Thin Lens Equation Calculator?
Enter the focal length of the lens and the object distance (both in meters) into the calculator. It will compute the image distance and magnification based on the Gaussian thin lens formula.
What does the magnification value indicate?
Magnification is the ratio of image height to object height. A positive magnification means the image is upright, while a negative magnification means it is inverted. The absolute value indicates size relative to the object.
Can this calculator handle both converging and diverging lenses?
Yes, if you enter a negative focal length for a diverging lens, the calculator will correctly compute the image distance and magnification, following the sign conventions of the thin lens equation.

Tips & Common Mistakes

Tips

  • Ensure both focal length and object distance are in meters to get the image distance in meters.
  • Use the sign convention: positive focal length for converging lenses, negative for diverging.
  • If the object distance is less than the focal length, the image will be virtual and upright.
  • Double-check your inputs for accuracy; small errors can significantly affect the calculated image distance.

Common Mistakes to Avoid

  • Forgetting to convert units to meters before entering values.
  • Using a positive focal length for a diverging lens, which leads to incorrect results.
  • Misinterpreting the sign of magnification: negative means inverted, not smaller.

Last updated: August 13, 2026