# Focal Diameter Calculator

## Now, What Exactly Is A “Focal Diameter Calculator”?

A focal diameter calculator is a tool that helps you find the value of a certain variable in a quadratic equation by completing the square.

## Free Focal Diameter Calculator With Steps

This is a very simple tool for Focal Diameter Calculator. Follow the given process to use this tool.

☛ Step 1: Enter the complete equation/value in the input box i.e. across “Provide Required Input Value:”

☛ Step 2: Click “Enter Solve Button for Final Output”.

☛ Step 3: After that a window will appear with final output.

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## Formula for focal diameter

The focal diameter is the distance from the center of a lens to its focal point.

D = 2*F*f

Where D is the focal diameter in meters, F is the focal length in meters, and f is the focal ratio.

## Focal Diameter Definition

The focal diameter is the distance between the two points on a lens that are in focus.

## Example of focal diameter based on Formula

The focal diameter of a lens is given by the formula:

f = (n/2) (D/f)

where n is the index of refraction of the lens, D is the lens diameter, and f is the focal length of the lens.

For example, if a lens has an index of refraction of n = 1.5, a diameter of D = 2 cm, and a focal length of f = 1 m, then the focal diameter of the lens is given by f = (n/2) (D/f) = (1.5/2) (2 cm/1 m) = 1.5 cm.