Diameter of Circle Calculator
Enter a circle's radius, area, or circumference to find its diameter — and the full circle profile.
Diameter of Circle Calculator
Our Diameter of Circle Calculator finds a circle's diameter from whichever measurement you already have — radius, circumference, or area — and fills in the rest of the circle's profile automatically.
What Is the Diameter of a Circle?
The diameter is the length of a straight line that passes through the center of a circle, connecting two points on opposite sides of its edge. It is always exactly twice the radius, and it's the widest distance across the circle.
Diameter Formulas
From Circumference: d = c ÷ π
From Area: d = 2√(A ÷ π)
Example Calculations
From Radius: r = 7
d = 2 × 7 = 14
✓ Diameter = 14, Circumference ≈ 43.98, Area ≈ 153.94
From Circumference: c = 43.98
d = 43.98 ÷ π ≈ 14
✓ Diameter ≈ 14, Radius ≈ 7, Area ≈ 153.94
From Area: A = 153.94
d = 2√(153.94 ÷ π) ≈ 14
✓ Diameter ≈ 14, Radius ≈ 7, Circumference ≈ 43.98
Features of Our Diameter of Circle Calculator
Who Can Use This Calculator?
👉 Try our Diameter of Circle Calculator to get a circle's full measurements from just one known value.