Free OnlineCalculators & Converters
Area Calculator
Calculate the area and perimeter of 7 shapes: rectangle, circle, triangle, trapezoid, parallelogram, ellipse, and regular polygon. Step-by-step formulas.
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Key Features — Area Calculator
7 shape types supported
Rectangle, circle, triangle, trapezoid
Parallelogram, ellipse, regular polygon
Perimeter calculation included
Heron's formula for triangle sides
Formula and steps shown
Why Use This Tool — Area Calculator
Free Online Area calculatorCalculate area — for EveryoneFast & Easy Area of rectangleArea of circle — 100% FreeFree Online Area of triangleArea formula calculator — for Everyone
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Frequently Asked Questions — Area Calculator
What is the formula for the area of a rectangle?
Area = length × width. Perimeter = 2 × (length + width). For a 4m × 6m rectangle: Area = 24 m², Perimeter = 20 m.
How do I calculate triangle area without height?
If you know all three sides, use Heron's formula: s = (a+b+c)/2, Area = √(s(s-a)(s-b)(s-c)). If you have two sides and the angle between them, use Area = ½ × a × b × sin(C). Enter three sides in the Triangle tab to use Heron's formula automatically.
What is the area of a regular polygon?
Area = (perimeter × apothem) / 2, where the apothem is the distance from the center to the middle of a side = s / (2 × tan(π/n)). For a regular hexagon with side 5: apothem ≈ 4.33, perimeter = 30, area ≈ 64.95.