103 LearnersLast updated on June 25th, 2025
Perimeter Calculator
Calculators are reliable tools for solving simple mathematical problems and advanced calculations like trigonometry. Whether you’re cooking, tracking BMI, or planning a construction project, calculators will make your life easy. In this topic, we are going to talk about perimeter calculators.
What is a Perimeter Calculator?
A perimeter calculator is a tool used to determine the total distance around the edge of a two-dimensional shape. Whether it's a rectangle, circle, triangle, or any polygon, the calculator helps quickly compute the perimeter, saving time and effort.
How to Use the Perimeter Calculator?
Given below is a step-by-step process on how to use the calculator:
Step 1: Select the shape: Choose the shape for which you want to calculate the perimeter.
Step 2: Enter the dimensions: Input the required dimensions (like length and width for rectangles, radius for circles) into the given fields.
Step 3: Click on calculate: Click on the calculate button to get the result.
Step 4: View the result: The calculator will display the perimeter instantly.
How to Calculate the Perimeter?
To calculate the perimeter, different formulas are used based on the shape:
- Rectangle: Perimeter = 2 × (Length + Width)
- Circle: Perimeter (Circumference) = 2 × π × Radius
- Triangle: Perimeter = Side1 + Side2 + Side3
- Regular Polygon: Perimeter = Number of Sides × Side Length These formulas help determine the total length around the given shape.
Tips and Tricks for Using the Perimeter Calculator
When using a perimeter calculator, there are a few tips and tricks to facilitate the process and avoid errors:
- Ensure the correct units are used and consistent when inputting dimensions.
- Double-check that all sides of a polygon are accounted for, especially irregular ones.
- For circles, use a precise value of π (such as 3.14159) for more accurate results.
Common Mistakes and How to Avoid Them When Using the Perimeter Calculator
Even with calculators, mistakes can occur. Here are some common errors and how to avoid them:
Mistake 1
Neglecting unit consistency.
Ensure that all measurements are in the same unit before calculating. Mixing feet with inches, for example, can lead to incorrect results.
Mistake 2
Forgetting to include all sides in irregular polygons.
Make sure to add up all the sides manually before inputting them into the calculator for irregular polygons.
Mistake 3
Incorrectly using the formula for the shape.
Double-check that you are using the right formula for the shape you are calculating, such as using the circumference formula for a circle.
Mistake 4
Over-relying on the calculator for precision.
While calculators provide quick results, always consider rounding or decimal precision, especially in practical applications.
Mistake 5
Assuming all calculators handle all shapes.
Ensure the calculator you are using can handle the specific shape and its dimensions. Some calculators are limited in the types of shapes they can calculate.
Perimeter Calculator Examples
Problem 1
What is the perimeter of a rectangle with a length of 8 cm and a width of 3 cm?
Use the formula:
Perimeter = 2 × (Length + Width)
Perimeter = 2 × (8 + 3) = 2 × 11 = 22 cm
The perimeter of the rectangle is 22 cm.
Explanation
By adding the length and width, and then multiplying by 2, we get the total perimeter of the rectangle.
Problem 2
Calculate the circumference of a circle with a radius of 7 m.
Use the formula:
Circumference = 2 × π × Radius
Circumference = 2 × 3.14159 × 7 ≈ 43.98 m
The circumference of the circle is approximately 43.98 m.
Explanation
We multiply the radius by 2π to get the circumference of the circle.
Problem 3
Find the perimeter of a triangle with sides measuring 5 cm, 6 cm, and 7 cm.
Use the formula:
Perimeter = Side1 + Side2 + Side3
Perimeter = 5 + 6 + 7 = 18 cm
The perimeter of the triangle is 18 cm.
Explanation
By summing the lengths of all three sides, we determine the perimeter of the triangle.
Problem 4
How do you calculate the perimeter of a square with a side length of 4 inches?
Use the formula:
Perimeter = 4 × Side Length
Perimeter = 4 × 4 = 16 inches
The perimeter of the square is 16 inches.
Explanation
By multiplying the side length by 4, we get the total perimeter of the square.
Problem 5
What is the perimeter of a regular hexagon with each side measuring 9 meters?
Use the formula:
Perimeter = Number of Sides × Side Length
Perimeter = 6 × 9 = 54 meters
The perimeter of the hexagon is 54 meters.
Explanation
Multiplying the side length by the number of sides gives us the perimeter of the hexagon.
FAQs on Using the Perimeter Calculator
1.How do you calculate the perimeter of a rectangle?
2.What is the formula for the circumference of a circle?
3.How do you find the perimeter of a polygon?
4.Is the perimeter calculator accurate?
5.Can the perimeter calculator handle all shapes?
Glossary of Terms for the Perimeter Calculator
- Perimeter: The total length around a two-dimensional shape.
- Rectangle: A four-sided shape with opposite sides equal.
- Circumference: The perimeter of a circle.
- Regular Polygon: A shape with all sides and angles equal.
- π (Pi): A mathematical constant approximately equal to 3.14159, used in circle calculations.
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Seyed Ali Fathima S
About the Author
Seyed Ali Fathima S a math expert with nearly 5 years of experience as a math teacher. From an engineer to a math teacher, shows her passion for math and teaching. She is a calculator queen, who loves tables and she turns tables to puzzles and songs.
Fun Fact
: She has songs for each table which helps her to remember the tables
