Aumento Linear Lente
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
A = −d_i/d_o
About this calculator
The Linear Magnification Calculator for Converging Lenses determines the transverse linear magnification of an image formed by a converging lens. The linear magnification (A) is the ratio of image height to object height, given by the formula A = -d_i / d_o, where d_i is the image distance and d_o is the object distance. The negative sign indicates that the image is inverted relative to the object. This tool is useful in geometric optics to predict image size and orientation.
To use the calculator, enter the object distance (d_o) and image distance (d_i) in centimeters. The result shows the linear magnification, which can be greater than 1 (enlarged image), less than 1 (reduced image), or equal to 1 (same size). The calculator also indicates whether the image is real or virtual based on the sign of d_i: positive d_i indicates a real and inverted image; negative d_i indicates a virtual and upright image.
This calculator is applied in situations such as projectors, cameras, and magnifying glasses. For example, when projecting an image onto a screen, you can calculate the magnification to size the object. Caution: the formula assumes thin lenses and ideal conditions (no aberrations). Also, ensure you use the correct sign convention (real object: d_o positive; real image: d_i positive).
Another caution is that linear magnification does not account for the focal length of the lens. To relate d_o and d_i to focal length, use the thin lens equation: 1/f = 1/d_o + 1/d_i. This calculator is complementary to that equation, allowing you to compute magnification after finding d_i.
Frequently asked questions
What does negative linear magnification mean?
Negative linear magnification indicates that the image is inverted relative to the object, i.e., upside down.
Can I use this calculator for diverging lenses?
No, this calculator is specific to converging lenses. Diverging lenses produce virtual images and the magnification is positive, but the formula and sign convention are different.
What if the image distance is negative?
A negative image distance means the image is virtual (on the same side of the lens as the object). The magnification will be positive, indicating an upright image.
What unit should I use for distances?
Use centimeters for both distances. Magnification is dimensionless, so any consistent unit works, but the calculator expects cm.
How do I find the image distance if I don't know it?
You first need to use the thin lens equation (1/f = 1/d_o + 1/d_i) to calculate d_i, given the object and focal length. Then use this calculator for magnification.