The perimeter of a rectangle tells us the total distance around it. Whether you are fencing land, designing a frame, or solving a geometry problem, this formula helps you quickly measure the boundary length of any rectangular shape. It is one of the simplest and most commonly used formulas in maths and in real-life applications.
Formula for Calculating the Perimeter of a Rectangle - Overview
| Formula | Variables & Meaning | When It Is Used |
|---|---|---|
| P = 2 × (l + b) | l = length, b = breadth | When you need the total outer boundary of a rectangle |
What is Perimeter of a Rectangle in Maths?
In mathematics, the perimeter of a rectangle is the sum of the lengths of all four sides. Since opposite sides are always equal, the formula becomes 2 × (length + breadth). This makes it easy to calculate the boundary measurement of any rectangular figure.
A rectangle has two pairs of equal, parallel sides. If you add them individually:
length + breadth + length + breadth,
you get:
2 × (length + breadth) — which is the standard perimeter formula.
For example, if length = 20 m and breadth = 10 m,
then:
Perimeter = 2 × (20 + 10) = 60 m
This formula is useful in everyday tasks like fencing plots, creating frames, designing rectangular objects, and solving problems in exams such as CUET, SSC, Banking, and JEE.
Examples to Calculate Perimeter of a Rectangle
Example 1: Length = 15 cm, Breadth = 8 cm
Step 1: Formula → P = 2 × (l + b)
Step 2: P = 2 × (15 + 8)
Step 3: P = 2 × 23 = 46 cm
So, the perimeter of the rectangle is 46 cm.
Example 2: Length = 25 m, Breadth = 12 m
Step 1: Formula → P = 2 × (l + b)
Step 2: P = 2 × (25 + 12)
Step 3: P = 2 × 37 = 74 m
So, the perimeter of the rectangle is 74 m.
FAQs about Perimeter of a Rectangle Formula
Q1. What is the perimeter of a rectangle?
It is the total distance around the rectangle, calculated using 2 × (l + b).
Q2. What unit is used for perimeter?
Perimeter is measured in linear units like cm, m, or km.
Q3. How is perimeter different from area?
Perimeter measures the boundary length; area measures the surface inside.
Q4. Where is the perimeter of a rectangle used in real life?
It is used in fencing, flooring, construction, and designing borders.
Q5. Is the formula the same for a square?
No. A square has equal sides, so perimeter = 4 × side.
Q6. Can we find perimeter if only area is given?
Not directly, you must know at least one side length to calculate it.