Rectangle Area and Perimeter Calculator

Welcome to our Rectangle Area and Perimeter Calculator page.

We explain how to find the area and perimeter of a rectangle and provide a quick calculator to work them out for you, step-by-step.

There are also some worked examples and links to some worksheets where you can practice this skill.

Rectangle Area and Perimeter Calculator

This calculator finds the area and perimeter of a rectangle when the side lengths are known.

Rectangle Area & Perimeter Calculator

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  1. Choose the length and width of the rectangle: you can choose a whole number, decimal or fraction.
    • You can type a fraction by typing the numerator then '/' then the denominator.
    • You can type a mixed number by typing the whole-number part, then a space then the fraction part.
    • Examples: 2 1/2 (two and one-half); 3 4/5 (three and four-fifths); 7 1/3 (seven and one-third).
  2. Choose your units of measurement (default is none)
  3. Choose your desired accuracy (default is 2 decimal places)
  4. Click the Find Area & Perimeter button
  5. You will be shown the area and perimeter as a decimal (and also a fraction if you typed the length as a fraction).

What is the Area and Perimeter of a Rectangle?

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The area of a rectangle is the amount of space inside the rectangle.

The perimeter of a rectangle is the distance around the edge of the rectangle.

Area and Perimeter of a Rectangle Formula

area of a rectangle formula image

The formula for the area of a rectangle is: \[ A = l \cdot w \; \]

where l is the length and w is the width of the rectangle

The formula for the perimeter of a rectangle is: \[ P = 2l + 2w \; \]

where l is the length and w is the width of the rectangle

Area of a Rectangle Examples

Area and Perimeter of a Rectangle Example 1

Find the area and perimeter of the rectangle below.

area of a rectangle example 1

The length of rectangle is 12 cm and the width is 7 cm.

The area of a rectangle

\[ A = l \cdot w \; \] where l is the length and w is the width of the rectangle.

So if we substitute the values of the length and width into this equation, we get: \[ A = 12 \times 7 = 84 \]

The area of the rectangle is 84 cm2.

The perimeter of a rectangle

\[ P = 2l + 2w \; \]

So if we substitute the values of the length and width into this equation, we get: \[ P = (2 \times 12) + (2 \times 7) = 24 + 14 = 38 \]

The perimeter of the rectangle is 38 cm.

Area and Perimeter of a Rectangle Example 2

Find the area and perimeter of the rectangle below.

area of a rectangle example 2

The length of rectangle is 2.4 m and the width is 0.7 m.

The area of a rectangle

\[ A = l \cdot w \; \] where l is the length and w is the width of the rectangle.

So if we substitute the values of the length and width into this equation, we get: \[ A = 2.4 \times 0.7 = 1.68 \]

The area of the rectangle is 1.68 m2.

The perimeter of a rectangle

\[ P = 2l + 2w \; \]

So if we substitute the values of the length and width into this equation, we get: \[ P = (2 \times 2.4) + (2 \times 0.7) = 4.8 + 1.4 = 6.2 \]

The perimeter of the rectangle is 6.2 m.

Area and Perimeter of a Rectangle Example 3

Find the area and perimeter of the rectangle below leaving your answer for the area as a mixed fraction.

area of a rectangle example 3

Although this shape is tilted, it is still a rectangle.

The length of rectangle is 3 ½ inches and the width is 8 ½ inches.

The area of a rectangle

\[ A = l \cdot w \; \] where l is the length and w is the width of the rectangle.

So if we substitute the values of the length and width into this equation, we get: \[ A = 3 {1 \over 2} \times 8 {1 \over 2} = {7 \over 2} \times {17 \over 2} \]

Multiplying the fractions together gives us: \[ A = {7 \times 17 \over 2 \times 2} = {119 \over 4} = 29 {3 \over 4} \]

The area of the rectangle is 29 ¾ in2.

The perimeter of a rectangle

\[ P = 2l + 2w \; \]

So if we substitute the values of the length and width into this equation, we get: \[ P = 2 \times 3 {1 \over 2} + 2 \times 8 {1 \over 2} = 7 + 17 = 24 \]

The perimeter of the rectangle is 24 inches.

Area and Perimeter of a Rectangle Example 4

Find the area and perimeter of the rectangle below. Give your answer in cm or cm2.

area of a rectangle example 4

The length of rectangle is 2.1 m and the width is 45 cm.

First we need to convert 2.1 m into cm so that both measurements have the same units of measure.

1 m = 100 cm so 2.1 m = 2.1 x 100 = 210 cm

The area of a rectangle

\[ A = l \cdot w \; \] where l is the length and w is the width of the rectangle.

So if we substitute the values of the length and width into this equation, we get: \[ A = 210 \times 45 = 9450 \]

The area of the rectangle is 9450 cm2.

The perimeter of a rectangle

\[ P = 2l + 2w \; \]

So if we substitute the values of the length and width into this equation, we get: \[ P = (2 \times 210) + (2 \times 45) = 420 + 90 = 510 \]

The perimeter of the rectangle is 510 cm.

You can use our Rectangle area and perimeter calculator to check any of these examples out!

More Area & Perimeter Support and Resources

We have a range of other area worksheets and support pages for a range of different 2d shapes.

More Area & Volume Calculators

We have a range of area and volume calculators to help you find the area and volumes of a range of different 2d and 3d shapes.

Each calculator page comes with worked examples, formulas and practice worksheets.

 

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How to Print or Save these sheets

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Need help with printing or saving?
Follow these 3 easy steps to get your worksheets printed out perfectly!

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