Circle Length Calculator

Radius r, diameter d, and circumference c are related. The higher the radius or the diameter, the higher the circumference. The circle length formula connects these variables in a single equation:

c = 2πr

If you only know the diameter, you can find the length of the radius of the circle by simply remembering the diameter is twice the radius:

r = d/2

Reordering the equations, you can also calculate the length of the circle diameter in terms of the circumference:

d = c/π

Similarly, you can know what the length of the radius of the circle is:

r = c/(2π)

Let's suppose you want to know what is the length of the radius of a circle of 10 cm circumference. You can follow these steps:

1. Use an adequate formula to solve your problem. In this case, it would be r = c/(2π).
2. Input the circumference in the formula. The result should be: r = 10cm / (2π).
3. Double-check your results. Input 10 cm in the circumference box of the circle length calculator. The result should also be 1.59155 cm for the radius.

Now that you know how to find the length of a circle, you can look at these other great tools and keep improving your skills:

• Circle calc: find c, d, a, r;
• Circle measurements calculator;
• Circle formula calculator;
• Radius of a circle calculator;
• Circumference to diameter 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.