# Calculate diameter

Calculate the diameter of the circumference is very simple although there are several possibilities to do it.

Thanks to our calculator you will be able to find the diameter of the circle from its radius or from its perimeter or length.

## Calculating the diameter of a circle from the radius

If we know the radius of the circumference, calculate its diameter (d) is very easy from the following mathematical formula:

It is enough to multiply by two the radius to obtain the value of the diameter. For example, if we have a circle whose radius is 3 centimeters, then its diameter will be 6 cm.

Let's look at another example in which we are asked for calculate the diameter of the Earth. We know that its radius is 6,371 km, therefore:

d = 6371 x 2 = 12,742 kilometers:

## Calculate diameter of circumference knowing perimeter

If instead of the radius we are given the length of the circle, we are going to show you how to calculate the diameter of a circumference knowing the length.

To this end, it is not a bad idea to review the concept of perimeter of a circle because, thanks to it, we will obtain the formula for calculating the diameter:

d = perimeter / π

If you do not remember how much is PI worthyou can substitute its value for 3.141516.

As a solved exercise, we will see what is the diameter of a circle whose perimeter is 12 centimeters:

d = 12 cm / 3.1415 = 3.819 cm

## To get the diameter of a circle from its area

Finally, there is a third possibility for find the diameter of a circle knowing its area or surface. In this case, the formula we will use will be the following:

d = 2 x √(A/π)

That is, the diameter is obtained by multiplying by two the result of the square root of the area of the circle between PI. To make the operation clearer, we are going to see it with an example in which we are given a 12 cm circumference2 and ask us to find its diameter:

d = 2 x √(12 cm2/3,14) = 2 x √(3,82) = 2 x 1,95 = 3,9 cm

## Calculate the diameter of a wheel

If you want to calculate the diameter of a wheeldon't miss our tire equivalence calculator with which you can compare two different wheels and compare their parameters to see if you can mount them on your car without homologation.

If you have any doubts about any of the three methods we have seen or you have been given a problem that you do not know how to solve, leave us a comment and we will help you find the right solution.