The formula to calculate the area of a circle using radius is as follows: Area of a circle = π × r2. And, to calculate the area of a circle using diameter use the following equation: Area of a circle …

See How to Calculate the Area below, but first the calculator: Enter the radius, diameter, circumference or area of a Circle to find the other three.

Oct 29, 2025 · To find the area of a circle, use the formula A = π • r2, where r is the radius of the circle. If you only know the diameter of the circle, then use the formula A = π • (d/2)2 where d …

Aug 1, 2025 · Use this circle calculator to find the area, circumference, radius or diameter of a circle. Given any one variable A, C, r or d of a circle you can calculate the other three …

Oct 25, 2023 · The area of a circle can be calculated using three different formulas. The formulas are used based on whether the radius, diameter, or circumference is known to us.

Jul 2, 2025 · Calculate the area of a circle using radius or diameter, with an optional custom π value. Formulas: A = π × r² or A = π × (d ÷ 2)².

Area of a circle The area of a circle is the plane region bounded by the circle's circumference. The region shaded in gray inside of circle A above is its area. The area of a circle can be found …

Jun 9, 2025 · Learn how to find the area of a circle with clear formulas, step-by-step examples, and visual explanations—perfect for students and math learners of all levels.

Apr 29, 2025 · Learn how to calculate the area of a circle with step-by-step examples. Includes formulas, derivation, practical applications, and practice problems...

Nov 29, 2025 · Free circle area calculator. Calculate area from radius or diameter. Find radius, diameter, and circumference from area. Supports multiple units with visual diagram.