Math
Rectangle
Find area and perimeter from two sides.
Calculators / Math / Pythagorean theorem
Pythagorean theorem calculator
Find the hypotenuse of a right triangle.
On this page
Hypotenuse5
Area6square units
Calculator controls
How to calculate
Find the hypotenuse of a right triangle.
c = √(a² + b²)
Worked example
Side a: 3; Side b: 4.
Hypotenuse: 5 ; Area: 6 square units.
Assumptions and limits
Both perpendicular sides must use the same unit.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
The hypotenuse is opposite the right angle and is longer than either input side. Area is half the product of the two perpendicular sides.
When this tool is useful
Find the diagonal of a rectangular space when both sides use the same unit.
Understanding your inputs
| Input | What to enter |
|---|---|
| Side a | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Side b | Enter a number of at least 0.000001 and no more than 1000000000000. |
Frequently asked questions
Can I use this for any triangle?
No. The two entered sides must meet at exactly 90 degrees. An oblique triangle needs a different relationship.
What units does the answer use?
The hypotenuse uses the same length unit as the inputs. If the sides are metres, area is in square metres.