# 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

Rectangle Area & Perimeter Calculator 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).

### Area and Perimeter of a Rectangle Formula The formula for the area of a rectangle is: $A = l \times w \;$

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

The formula for the perimeter of a rectangle is: $P = 2l + 2w \; or \; 2 (l + w)$

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

### Area and Perimeter of a Rectangle Examples

#### Area and Perimeter of a Rectangle Example 1

Find the area and perimeter of the rectangle below. The length of rectangle is 12 cm and the width is 7 cm.

The area of a rectangle

$A = l \times w \;$ 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. The length of rectangle is 2.4 m and the width is 0.7 m.

The area of a rectangle

$A = l \times w \;$ 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

$P = 2(l + w) \;$

So if we substitute the values of the length and width into this equation, we get: $P = 2 \times (2.4 + 0.7) = 2 \times 3.1 = 6.2$

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. 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

$A = l \times w \;$ 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

$P = 2(l + w) \;$

So if we substitute the values of the length and width into this equation, we get: $P = 2 \times (3 {1 \over 2} + 8 {1 \over 2}) = 2 \times 12 = 24$

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. 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

$A = l \times w \;$ 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

$P = 2(l + w) \;$

So if we substitute the values of the length and width into this equation, we get: $P = 2 \times (210 + 45) = 2 \times 255 = 510$

The perimeter of the rectangle is 510 cm.

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

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