Perimeter Of A Right Triangle
Calculate the perimeter of a right triangle from its two legs. Includes hypotenuse and area with this free online right triangle perimeter calculator.
About This Calculator
This free online Perimeter of a Right Triangle Calculator computes the perimeter, hypotenuse length, and area of a right triangle from its two leg lengths. It is designed for students learning geometry, teachers preparing lesson materials, construction workers measuring right-angle corners, and DIY enthusiasts planning projects. Simply enter the lengths of the two perpendicular sides (legs), and the calculator instantly returns all three key measurements.
The calculator uses the Pythagorean theorem to find the hypotenuse: c = √(a² + b²), where a and b are the leg lengths. The perimeter is then calculated by summing all three sides: P = a + b + c. The area is computed using the standard right triangle area formula: Area = ½ × a × b, because the two legs serve as the base and height. These formulas are universally applicable regardless of measurement units — you can use inches, feet, centimeters, meters, or any other unit, as long as both leg inputs use the same unit.
How to use: Enter the length of Leg A and Leg B in the input fields above. Click "Calculate" to instantly see the perimeter (the total distance around the triangle), the hypotenuse length (the longest side opposite the right angle), and the area (the space enclosed by the triangle). All results are displayed with two decimal places for precision.
Regional Notes: This is a mathematical calculator based on universally accepted geometric principles. The Pythagorean theorem and perimeter and area formulas apply identically worldwide, in all countries including India, the United States, and the United Kingdom. No region-specific constants or conversions are required.
Frequently Asked Questions
How do you find the perimeter of a right triangle?
Add all three sides: perimeter = a + b + c, where a and b are the legs and c is the hypotenuse. The hypotenuse is found using the Pythagorean theorem: c = √(a² + b²).
What else does this calculator show?
Besides the perimeter, it also shows the hypotenuse length and the area of the right triangle.
Can I calculate perimeter from just the legs?
Yes, enter the two leg lengths and the calculator will find the hypotenuse automatically before computing the perimeter.
What is the area formula shown?
Area = ½ × leg¹ × leg², since the legs are perpendicular in a right triangle.
What units should I use?
You can use any unit of length (inches, feet, centimeters, meters, etc.) as long as both legs use the same unit. The result will be in the same unit squared for area.
Can I use this for an isosceles right triangle?
Yes, for an isosceles right triangle where both legs are equal, simply enter the same value for Leg A and Leg B. The hypotenuse will be leg × √2.
What is the Pythagorean theorem?
The Pythagorean theorem states that in a right triangle, the square of the hypotenuse equals the sum of squares of the other two sides: c² = a² + b². This is the fundamental relationship used to find the missing side.
Is this tool free?
Yes, all calculators on Calculy are completely free to use with no registration required.