# How to calculate the perimeter of a rectangle

**Introduction**

Calculating the perimeter of a rectangle is a basic skill that’s essential in mathematics, especially in geometry. Whether you are a student, a designer, or just someone who likes to keep their mental math sharp, this guide will assist you in finding the perimeter of any rectangle.

**What is a Rectangle?**

A rectangle is a quadrilateral – a shape with four straight sides and four right angles (90° angles). Opposite sides of the rectangle have equal length. In simpler terms, it’s a four-sided figure with two pairs of parallel sides that have different lengths.

**Understanding Perimeter**

The perimeter is the total length of all outer edges (sides) of a two-dimensional shape. In the case of rectangles, this means adding up the lengths of all four sides.

**Formula for Calculating the Perimeter of a Rectangle**

The formula for calculating the perimeter (P) of a rectangle is:

**P = 2(length + width)**

Where “length” (L) represents the longer side, and “width” (W) represents the shorter side. By doubling the sum of their lengths, you get the total distance around the shape.

**Step-by-Step Guide to Calculate the Perimeter of a Rectangle**

**Step 1: **Measure or find out the length and width of your rectangle. If you have an existing object or plan, check for dimensions. If measuring yourself, use a ruler or tape measure to record accurate measurements.

**Step 2: **Write down your measurements on paper or type them into a calculator as Length (L) and Width (W).

**Step 3: Add together Length (L) and Width (W). **

The equation should look like this:

**L + W = Sum**

**Step 4: Multiply the sum by 2. This represents twice the sum of L and W.**

The equation should look like this:

**2(L + W) = Perimeter**

**Step 5: Write down or take note of your answer. The result is the perimeter of the rectangle.**

**Example:**

Let’s say that we have a rectangle with a length of 10 units and a width of 5 units.

**Step 1: **Length (L) = 10 units, Width (W) = 5 units

**Step 2:** Write down L = 10 and W = 5.

**Step 3:** L + W = 10 + 5 = 15

**Step 4:** Multiply by 2: 2(L + W) = 2(15) =30

**Step 5: **The perimeter of the rectangle is equal to 30 units.

**Conclusion**

Calculating the perimeter of a rectangle is as simple as adding the length and width and then multiplying by two. Understanding this basic geometrical concept not only helps in mathematics but also in everyday tasks like designing layouts, measuring materials for construction, or planning spaces. Practice calculating with different sizes of rectangles to improve your mental math skills.