Calculate magnification from object and image distance, object and image size, microscope lens settings, or telescope focal lengths.

Magnification Calculator

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Magnification Formula

The following equation is commonly used to calculate the magnification magnitude (absolute value) of a thin lens from the object and image distances.

|m| = \left|\frac{v}{u}\right|
  • Where |m| is the magnification magnitude (absolute value)
  • v is the image distance (distance from the lens to the image)
  • u is the object distance (distance from the lens to the object)

To calculate a magnification magnitude, divide the image distance by the object distance. Under common thin-lens sign conventions, the signed magnification is often written as m = −v/u (the negative sign indicates an inverted real image).

Magnification Definition

Magnification is a dimensionless quantity that describes image scaling. For linear (lateral) magnification, it is defined as the ratio of image height to object height: m = hi/ho. For a thin lens, this same magnification is related to distances by m = −v/u (or, in magnitude, |m| = |v/u|).

Magnification Example

How to calculate magnification?

  1. First, determine the distance of the object from the lens.

    Using a measurement device, determine the total distance from the object to the lens.

  2. Next, determine the distance of the image formed by the lens.

    As done in step 1, measure the total distance of the image formed by the lens.

  3. Finally, calculate the magnification.

    Plug the values from steps 1 and 2 into the formula to calculate the magnification.

FAQ

What is magnification?

Magnification is a dimensionless quantity that describes how large (or small) an image is compared with the object (for example, linear magnification is m = hi/ho). Magnification can be greater than 1 or less than 1, and the sign of m (if used) indicates image orientation.

What does a magnification value mean?

A magnification value of 3, for example, means that the image is 3 times the size of the object (in linear dimensions).