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Area of Rectangle Calculator

Calculate area from length and width.

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Area

Formula first

Overview

The area of a rectangle is the measure of the two-dimensional space enclosed within its four boundaries, where opposite sides are parallel and all interior angles are exactly 90 degrees. This fundamental geometric property is calculated as the product of its two perpendicular dimensions, typically designated as length and width.

Symbols

Variables

l = Length, w = Width, A = Area

Length
cm
Width
cm
Area

Apply it well

When To Use

When to use: This formula is applicable to any flat four-sided polygon with right angles. It assumes a Euclidean plane and requires that the length and width are measured in the same linear units.

Why it matters: Calculating the area of a rectangle is a foundational skill in spatial analysis, used for determining floor space in construction, quantifying land in real estate, and measuring screen sizes in electronics. It serves as the basis for understanding more complex surface area and volume calculations in higher mathematics.

Avoid these traps

Common Mistakes

  • Adding sides (Perimeter) instead of multiplying.
  • Mixed units (cm and m).

One free problem

Practice Problem

Practice Problem 1

A rectangular garden has a length of 12 meters and a width of 5 meters. What is its total area in square meters?

Length12 cm
Width5 cm

Solve for:

Hint: Multiply the two given dimensions together.

Practice Problem 2

A floor plan shows a room with an area of 48 square feet. If the width of the room is 6 feet, what is its length in feet?

Area48 cm^2
Width6 cm

Solve for:

Hint: Divide the total area by the given width.

Practice Problem 3

A piece of fabric has an area of 150 square centimeters and a length of 15 centimeters. Find its width in centimeters.

Area150 cm^2
Length15 cm

Solve for:

Hint: Divide the area by the length to find the missing side.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. Britannica: Area
  2. Wikipedia: Area (mathematics)
  3. Halliday, Resnick, Walker, *Fundamentals of Physics*, 10th ed.
  4. Britannica, The Editors of Encyclopaedia. 'Area'. *Encyclopedia Britannica*, 19 Mar. 2024.
  5. Wikipedia: Area
  6. Britannica: Euclidean geometry
  7. Wikipedia: Non-Euclidean geometry
  8. Standard curriculum — Primary / GCSE Foundation Maths