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Area Calculator


Note: Only enter the dimensions needed for your selected shape. Leave unrelated fields blank. All dimensions must be positive numbers.

Quick guide: Rectangle (width, height) • Square (side) • Circle (radius) • Triangle (base, height) • Parallelogram (base, height) • Trapezoid (base a, base b, height) • Ellipse (semi-major a, semi-minor b) • Sector (radius, angle in degrees).

Tip: Choose your preferred unit. Results are displayed in squared units (e.g., cm²).

Use our Area Calculator to quickly find the area of common shapes like rectangles, circles, triangles, trapezoids, ellipses, and more. Enter your dimensions, choose units, and get precise results in seconds.

What is an Area Calculator?

An Area Calculator is a simple tool that computes the amount of two-dimensional space a shape covers. Whether you are planning flooring, painting walls, cutting materials, or solving geometry problems, calculating area helps you estimate quantities, reduce waste, and make accurate decisions. Our calculator supports multiple shapes and units, so you can work the way you prefer.

How to Use the Area Calculator

  1. Select a shape from the dropdown (e.g., Rectangle, Circle, Triangle).
  2. Enter only the dimensions required for that shape.
  3. Pick your measurement unit (mm, cm, m, in, ft, or yd).
  4. Click Calculate Area to get the result in squared units.

Each shape uses its standard geometric formula. For example, a rectangle’s area is width × height, a triangle’s is 1/2 × base × height, and a circle’s is ? × r². The calculator applies these formulas automatically based on your selection.

Supported Shapes and Formulas

  • Rectangle: Area = width × height
  • Square: Area = side²
  • Circle: Area = ? × r²
  • Triangle: Area = 1/2 × base × height
  • Parallelogram: Area = base × height
  • Trapezoid: Area = (a + b) / 2 × height
  • Ellipse: Area = ? × a × b (semi-axes a and b)
  • Circular Sector: Area = (?/360) × ? × r²

Why Accurate Area Matters

Accurate area measurements prevent over- or under-buying materials. For home projects, it can mean purchasing the right amount of paint, tiles, or turf. In education, it reinforces understanding of geometry and units. For engineering and fabrication, precision translates into cost savings and quality outcomes.

Tips for Reliable Results

  • Measure carefully and use consistent units for all inputs.
  • Convert irregular shapes into combinations of supported shapes when possible.
  • For circular or elliptical shapes, measure radii or semi-axes from the center.
  • Double-check angles for sectors; the calculator expects degrees.

Common Use Cases

From laying sod in a backyard to calculating fabric for a craft project, the Area Calculator adapts to many contexts. Contractors can estimate flooring area by breaking a room into rectangles and triangles. Students can verify homework solutions by comparing manual calculations to the calculator’s output. DIY enthusiasts can plan paint coverage for accent walls, or compute the area of circular tabletops before ordering custom glass.

Units and Conversions

The calculator outputs results in the squared unit you select. For instance, if you choose centimeters, your result appears in cm². If you need to switch units, simply change the unit and re-calculate. This avoids conversion errors and ensures clarity when communicating measurements to suppliers or teammates.

Get Started

Pick your shape, enter your measurements, and press Calculate Area. Our tool handles the math so you can focus on planning and execution. It’s fast, free, and accurate—ideal for classrooms, work sites, and home projects alike.


FAQs

How does the Area Calculator handle different shapes?

Select a shape and enter only its required dimensions; the Area Calculator applies the correct formula automatically.

Can I change units in the Area Calculator?

Yes. Choose mm, cm, m, in, ft, or yd, and the Area Calculator reports results in squared units like cm² or ft².

What inputs are needed for a circle in the Area Calculator?

Enter the radius only. The Area Calculator uses A = ? × r² to compute the area.

Does the Area Calculator support triangles and trapezoids?

Yes. For triangles enter base and height; for trapezoids enter both bases and the height.

Is the Area Calculator accurate for ellipses?

Yes. Provide semi-major (a) and semi-minor (b) axes; it uses A = ?ab for precise results.

What does the Area Calculator output look like?

It shows a labeled result with the numerical area and the unit squared, plus the formula used.

Can the Area Calculator compute a sector’s area?

Yes. Enter the radius and the central angle in degrees; it calculates A = (?/360) × ? × r².

Do I need to fill all fields in the Area Calculator?

No. Only fill the fields needed for the selected shape; leave unrelated inputs blank.