Area Calculator

What Is an Area Calculator?

An area calculator is a tool used to determine the amount of two-dimensional space enclosed by a geometric shape. Different shapes require different mathematical formulas, so the calculation depends on the type of shape and the dimensions provided.

This free Area Calculator supports rectangles, squares, triangles, circles, trapezoids and parallelograms. It can be useful for mathematics, education, construction, home improvement, design, engineering and other situations where the area of a shape needs to be calculated.

Why Use the Area Calculator?

The calculator provides a simple way to calculate the area of several common geometric shapes without manually applying the relevant formula.

How to Use the Area Calculator

Follow these steps to calculate the area of a geometric shape.

1. Select a shape — Choose the geometric shape you want to calculate from the Shape menu.
2. Enter the dimensions — Enter the measurements requested for the selected shape.
3. Calculate the area — Select Calculate Area to perform the calculation.
4. Read the result — The calculated area and formula are displayed below the calculator.

How to Calculate Area

Area measures the surface contained within a two-dimensional boundary. The correct area formula depends on the shape being measured. For example, the area of a rectangle is calculated by multiplying its length by its width, while the area of a circle is calculated using pi multiplied by the radius squared.

The units used for the dimensions determine the unit of the resulting area. If measurements are entered in metres, the calculated area is in square metres. If measurements are entered in centimetres, the result is in square centimetres. Dimensions should therefore be entered using consistent units for the calculation to be meaningful.

Rectangle and Square Area

The area of a rectangle is calculated by multiplying its length by its width. A square is a special type of rectangle with four equal sides, so its area is calculated by multiplying one side by itself. For example, a rectangle measuring 8 metres by 5 metres has an area of 40 square metres.

Triangle and Circle Area

The area of a triangle is calculated by multiplying its base by its perpendicular height and dividing the result by two. The area of a circle is calculated by multiplying π by the square of its radius. These formulas are built into the calculator and applied automatically when the corresponding shape is selected.

Understanding Area Measurements

Area is expressed in square units because it describes two dimensions. Common metric units include square millimetres (mm²), square centimetres (cm²), square metres (m²) and square kilometres (km²). Imperial and US customary units include square inches (in²), square feet (ft²), square yards (yd²) and square miles (mi²).

This calculator does not convert between measurement units. It calculates the numerical area using the dimensions supplied. For accurate results, enter all dimensions for a particular calculation using the same unit. The calculator uses standard geometric formulas and JavaScript's mathematical precision to perform the calculation.

Frequently Asked Questions