Area Calculator
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How area calculation works
Area measures the 2-dimensional space a shape occupies, always expressed in square units — in², ft², cm², m², etc. Each geometric shape has a dedicated formula derived from its properties. This calculator applies the exact formula and shows you the full working, so you understand the result — not just the number.
Frequently asked questions
Circle area calculator
Use the circle area calculator to find the area of any circle. Formula: A = π × r², where r is the radius. Multiply pi (3.14159) by the radius squared. Example: a circle with radius 7 inches has an area of 153.94 in².
Square area calculator
Use the square area calculator to find the area of any square. Formula: A = s², where s is the length of one side. Example: a square with side 9 ft has an area of 81 ft².
Rectangle area calculator
Use the rectangle area calculator to find the area of any rectangle. Formula: A = w × h. Example: a rectangle 12 cm wide and 5 cm tall has an area of 60 cm².
Triangle area calculator
Use the triangle area calculator to find the area of any triangle. Formula: A = ½ × base × height. Example: a triangle with base 10 in and height 6 in has an area of 30 in².
Trapezoid area calculator
Use the trapezoid area calculator to find the area of any trapezoid. Formula: A = ½ × (a + b) × h. Example: parallel sides 8 ft and 5 ft, height 4 ft → area 26 ft².
Ellipse area calculator
Use the ellipse area calculator to find the area of any ellipse. Formula: A = π × a × b. Example: semi-axes 6 cm and 4 cm → area 75.40 cm².
Parallelogram area calculator
Use the parallelogram area calculator to find the area of any parallelogram. Formula: A = base × height. Example: base 10 m and height 3 m → area 30 m².
Sector area calculator
Use the sector area calculator to find the area of any circle sector. Formula: A = ½ × r² × θ. Example: radius 5 in and angle 90° → area 19.63 in².