Circumference to Diameter Calculator
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; andπ
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 circumferencetodiameter 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:

Use the appropriate equation, which, in this case, is the circumference to diameter formula:
c = πd

Input the diameter in the equation:
c = π × (5 cm) = 15.708 cm

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.
Othercircle related tools
Now that you know how to find circumference from diameter and viceversa, you can look at other tools related to circle calculations.
 Circle calc: find c, d, a, r;
 Circle measurements calculator;
 Circle formula calculator;
 Radius of a circle calculator;
 Circle length calculator;
 Circumference and area of a circle calculator;
 Diameter of a circle calculator;
 Circle perimeter calculator;
 Square footage of a circle calculator; and
 Square inches of a circle calculator.
FAQ
What is the circumference of a 6foot diameter circle?
18.8496 feet. To convert diameter to circumference:
 Take the diameter.
 Multiply it by the number pi (π).
 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.