Omni Calculator logo

Circumference to Diameter Calculator

Created by Luis Hoyos
Reviewed by Wojciech Sas, PhD
Last updated: Jan 18, 2024


The circumference to diameter calculator can help you solve the geometry problem of finding the diameter of a circle by inputting its circumference. This calculator works both ways, so you can also convert a diameter to a circumference.

Keep reading to learn more about:

  • The circumference to diameter formula.
  • How to calculate circumference from the diameter.
  • How to get diameter from the circumference.

The circumference to diameter formula

Diameter and circumference are lengths related to each other — the higher the diameter, the higher the circumference. The circumference to diameter formula connects these variables in a single equation:

d = c/π

where:

  • d stands for the diameter;
  • c stands for the circumference; and
  • π is the pi number.

If, on the other side, you're interested in how to calculate circumference from the diameter, you can solve for c in the above equation:

c = π × d

💡 Did you know?
As you can imagine from the above equations, the number π is a constant equal to the circumference-to-diameter ratio of a circle (π = c/d). If you divide the circumference by the diameter, independently of the size, it'll always be 3.14159265...

How to find circumference from diameter: an example

Let's look at an example. Suppose you want to find the circumference of a 5 cm diameter circle. These would be the steps to follow:

  1. Use the appropriate equation, which, in this case, is the circumference to diameter formula:

    c = πd

  2. Input the diameter in the equation:

    c = π × (5 cm) = 15.708 cm

  3. That's it. Also, check your results using our circumference to diameter calculator. Input 5 cm in the diameter box. Your result should also be 15.708 cm.

FAQ

What is the circumference of a 6-foot diameter circle?

18.8496 feet. To convert diameter to circumference:

  1. Take the diameter.
  2. Multiply it by the number pi (π).
  3. In this case, the circumference equals: π × 6 ft = 18.8496 ft.

How do I get diameter from circumference?

Divide the circumference value by the number pi (π), or use the formula d = c/π. That's how you find the diameter of a circle with its circumference.

Luis Hoyos
Image of a circle with radius, diameter, circumference and area marked.
Circumference (c)
in
Diameter (d)
in
Check out 11 similar circle calculators ⭕
Arc lengthArea of a circleCircle calc: find c, d, a, r… 8 more
People also viewed…

Ideal egg boiling

Quantum physicist's take on boiling the perfect egg. Includes times for quarter and half-boiled eggs.

Substitution method

Substitution method calculator shows you step-by-step how to solve systems of linear equations using the substitution method.

Titration

Use our titration calculator to determine the molarity of your solution.

Volume

Calculate the volume of numerous regular shapes with ease using our versatile volume calculator. Need to calculate the volume of a box? Try this tool.