Math July 13, 2026 · 8 Min Read

Hypotenuse Calculator – Guide & Formulas

Calculate the hypotenuse (c) of a right triangle instantly. Supports decimal outputs, square root simplify steps, and finds missing leg lengths.

Instantly find the hypotenuse or a missing leg of a right triangle using the Pythagorean theorem. Enter the lengths of the two legs to get the step-by-step solution.

Key Takeaway

Use the free Hypotenuse Calculator to calculate the hypotenuse (c) of a right triangle instantly. supports decimal outputs, square root simplify steps, and finds missing leg lengths. Get instant results with step-by-step explanations.

How to Use the Hypotenuse Calculator

  1. To find the hypotenuse, enter the lengths of both perpendicular legs (Side a and Side b).
  2. To find a missing leg, enter the known leg and the hypotenuse.
  3. Observe the precise decimal result and the step-by-step equation expansions.

The Formula

c = sqrt(a^2 + b^2)

Variable Definitions

  • a, b: The lengths of the perpendicular sides (legs)
  • c: The length of the hypotenuse

Finding the Hypotenuse of a 5-12 Right Triangle

A carpenter is laying out a corner and needs to verify the diagonal length of legs measuring 5 inches and 12 inches.

  1. Step 1: Set leg a = 5, leg b = 12.
  2. Step 2: Square both legs: 5² = 25, 12² = 144.
  3. Step 3: Add squared values: 25 + 144 = 169.
  4. Step 4: Take the square root of 169 to find hypotenuse c = 13.

Frequently Asked Questions

What is a Pythagorean triple?

A Pythagorean triple consists of three positive integers (a, b, c) that satisfy the formula, such as (3, 4, 5), (5, 12, 13), or (8, 15, 17).

Which side of a right triangle is the hypotenuse?

The hypotenuse is always the longest side and is situated directly opposite the 90-degree right angle.

Can a hypotenuse be shorter than one of the legs?

No. Geometrically, the hypotenuse must always be strictly longer than either individual leg.