📐 Area Calculator (with Units & Steps)

Rectangle

Triangle (3 sides)

Trapezoid

Circle

Sector

Ellipse

Parallelogram

Area Calculator: Formulas, Examples, and How to Calculate Area of Geometrical Shapes

Calculating the area of geometrical shapes using is an essential concept in mathematics, engineering, architecture, construction, and everyday problem-solving. Whether you are a student, teacher, or professional, using an online area calculator makes calculations faster, more accurate, and easier to understand.
In this guide, you’ll learn:

What area is and why it matters
Area formulas for different geometrical shapes
Step-by-step examples for each shape
How to use an area calculator with units

Area calculator infographic showing area formulas, step-by-step examples, and calculations for rectangle, triangle, circle, trapezoid, sector, ellipse, and parallelogram with an online area calculator interface and unit selection.

What Is Area?

Area is the amount of surface covered by a two-dimensional shape.
It is measured in square units, such as square meters (m²), square centimeters (cm²), square feet (ft²), or square inches (in²).
For example:

The area of a room helps determine how much flooring is needed
The area of land is used in construction and agriculture
The area of shapes is fundamental in geometry and physics

Why Use an Online Area Calculator?

An area calculator helps you:
Instantly calculate area without memorizing formulas
Avoid manual calculation errors
See step-by-step solutions for better understanding
Convert and display results in different units
Our area calculator supports multiple geometrical shapes and shows the complete solution clearly.

how to calculate area for Different Geometrical Shapes?

Below are the most commonly used area formulas, along with explanations and examples.

How to calculate the area of a Rectangle

Formula
Area = Length × Width
Example
If:
Length = 8 m
Width = 5 m
Calculation:

Area = 8 × 5 Area = 40 m²
Rectangles are widely used in room layouts, plots, and construction plans.

How to calculate the area of a Triangle (Three Sides – Heron’s Formula)

When only the three sides are known, we use Heron’s formula.
Formula

s = (a + b + c) / 2 Area = √[ s(s − a)(s − b)(s − c) ]
Example
Let:
a = 6 cm
b = 8 cm
c = 10 cm
Step 1:

s = (6 + 8 + 10) / 2 = 12
Step 2:

Area = √[12(12−6)(12−8)(12−10)] Area = √(12 × 6 × 4 × 2) Area ≈ 24 cm²

How to calculate the area of a trapezium?

A trapezoid has two parallel sides and a height.
Formula
Area = (a + b) / 2 × h
Example
If:
Base a = 10 m
Base b = 6 m
Height = 4 m

Area = (10 + 6) / 2 × 4 Area = 32 m²

How to calculate the area of a Circle?

Formula
Area = π × r²
Where π (pi) ≈ 3.1416
Example
Radius = 7 cm

Area = π × 7² Area ≈ 153.94 cm²
Circles are used in wheels, pipes, gardens, and design layouts.

How to calculate the area of a Sector ?

A sector is a portion of a circle defined by an angle.
Formula
Area = (θ / 360) × π × r²
Example
If:
Radius = 10 m
Angle = 90°

Area = (90 / 360) × π × 10² Area ≈ 78.54 m²

How to calculate the area of a an Ellipse?

An ellipse looks like a stretched circle.
Formula
Area = π × a × b
Where:
a = semi-major axis
b = semi-minor axis
Example
If:
a = 6 cm
b = 4 cm

Area = π × 6 × 4 Area ≈ 75.40 cm²

How to calculate the area of a Parallelogram?

Formula
Area = Base × Height
Example
If:
Base = 12 ft
Height = 5 ft

Area = 12 × 5 Area = 60 ft²

Units Used in Area Calculator

Square meters (m²)
Square centimeters (cm²)
Square millimeters (mm²)
Square feet (ft²)
Square inches (in²)

Conclusion

Understanding area formulas for geometrical shapes is essential for students and professionals alike. Using a modern area calculator not only saves time but also improves accuracy and learning through step-by-step solutions.
Whether you are calculating the area of a rectangle, triangle, circle, or ellipse, an online area calculator makes the process simple, fast, and reliable.