Magnifying Power Calculator

How to Use This Calculator

1. Enter the distance from your eye to the lens (D) in centimeters. A typical value for comfortable viewing is 25 cm.
2. Enter the focal length of the magnifying lens (f) in centimeters. This can usually be found in the lens specifications.
3. Click the "Calculate" button to compute the magnifying power.
4. The calculator will display the magnifying power (M) based on the formula M = (D + f) / f.

Working Principle

The magnifying power of a simple magnifier is determined by the distance you hold the lens from your eye and the focal length of the lens. When you look through a magnifying glass, the image is formed at a distance that depends on these two factors. The formula used in this calculator accounts for the fact that the magnifying power increases as the distance to the eye increases relative to the focal length.

Example

Suppose you have a magnifying glass with a focal length of 10 cm. If you hold it 25 cm from your eye, the magnifying power would be:

M = (25 cm + 10 cm) / 10 cm = 35 / 10 = 3.5x

Applications

This calculator is useful for:

• Designing simple magnifying devices
• Understanding the capabilities of magnifying glasses
• Optical experiments and educational purposes