What's the difference between area and perimeter?

Area measures the space inside a shape (expressed in square units), while perimeter measures the distance around the outside of a shape (expressed in linear units). For example, a 3×4 rectangle has an area of 12 square units and a perimeter of 14 units.

How do I calculate the area of irregular shapes?

For irregular shapes, you can break them down into smaller regular shapes (rectangles, triangles, circles), calculate each area separately, then add them together. Alternatively, use grid paper to count squares or apply calculus methods for complex curves.

Why is the circle area formula πr² and not πd²?

The formula πr² comes from calculus and integration. If you used diameter (d), the formula would be π(d/2)² = πd²/4. Using radius directly gives the simpler πr² formula. Remember that radius is half the diameter.

How do I find the area of a triangle if I only know the three sides?

Use Heron's formula: First find the semi-perimeter s = (a+b+c)/2, then Area = √[s(s-a)(s-b)(s-c)], where a, b, and c are the three side lengths. This works for any triangle when you know all three sides.

Area Calculator – Calculate Area of Shapes

Calculate the area of various geometric shapes including circles, rectangles, triangles, squares, and more. Our comprehensive area calculator provides formulas and step-by-step calculations for all common shapes.

Area Calculator – Calculate Area of Shapes

Shape*

Select the geometric shape

First Dimension*

Primary measurement (radius, length, side, etc.)

Second Dimension

Secondary measurement (width, height, etc.) if needed

Third Dimension

Third measurement for trapezoids

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Math visualization will appear here

Understanding Area Calculations

Area measures the amount of space inside a two-dimensional shape. It's expressed in square units (like square meters, square feet, or square inches) and is fundamental in geometry, construction, landscaping, and many practical applications.

Common Area Formulas

Essential area formulas for different shapes:

Circle: A = πr² (where r is the radius)
Rectangle: A = length × width
Triangle: A = ½ × base × height
Square: A = side²
Parallelogram: A = base × height
Trapezoid: A = ½ × (base₁ + base₂) × height
Ellipse: A = π × a × b (where a and b are the semi-axes)

How to Use This Calculator

Follow these simple steps to get accurate results:

Enter your shape
Enter your first dimension
Enter your second dimension
Enter your third dimension
Click the "Calculate" button to see your results
Review the detailed breakdown and explanation

Why Use Our Area Calculator – Calculate Area of Shapes?

100% free and no registration required
Instant, accurate calculations with professional formulas
Mobile-friendly design that works on any device
Privacy-focused - your data never leaves your browser
Educational content to help you understand the results

Frequently Asked Questions

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