Great news! We will be upgrading our calculator and lesson pages over the next few months. If you notice any issues, you can submit a contact form by clicking here.

Perimeter of a Rectangle

Learn how to find the perimeter of a rectangle.

Perimeter of a Rectangle Lesson

Rectangle Perimeter Formula

The formula for perimeter of a rectangle is given as:

P = 2(l + w)

Where P is the perimeter, l is the length, and w is the width.

Perimeter of a rectangle formula and diagram
Want unlimited access to Voovers calculators and lessons?
Join Now
100% risk free. Cancel anytime.

Perimeter of a Rectangle Example Problems

Let's work through a couple of example problems together to practice finding the perimeter of a rectangle.

Example Problem 1

Find the perimeter of a rectangle with a length of 12 and width of 5.


  1. The length and width are given to us. Let's plug the given dimensions into the formula.
  2. P = 2(l + w) = 2(12 + 5)
  3. P = 2(17) = 34
  4. The perimeter of the rectangle is 34.

Example Problem 2

A rectangle has a perimeter of 15 and a length of 5. What is the width?


  1. Let's plug the given dimensions into the formula, then isolate w to find the width.
  2. P = 2(l + w) → 15 = 2(5 + w)
  3. 15 = 10 + 2w
  4. 5 = 2w
  5. w = 2.5
  6. The width of the rectangle is 2.5.
Learning math has never been easier.
Get unlimited access to more than 168 personalized lessons and 72 interactive calculators.
Join Voovers+ Today
100% risk free. Cancel anytime.
Scroll to Top