Missing Right Triangle Leg Calculator

units
Enter hypotenuse in units.
units
Enter known leg in units.
Math

Missing Right Triangle Leg: calculate results from explicit inputs, with a formula and worked example.

Formula

missing leg = √[(hypotenuse−leg)(hypotenuse+leg)]

Example Calculation

Example inputs
  • Hypotenuse: 5 units
  • Known leg: 3 units

Hypotenuse 5 and leg 3 give the other leg 4.

Frequently asked questions

How do I use this calculator?

Enter hypotenuse, known leg. The result updates automatically. Use Reset to restore the example values.

What method does it use?

missing leg = √[(hypotenuse−leg)(hypotenuse+leg)]. Euclidean geometry. Use one consistent length unit; areas and volumes use its square and cube. Degenerate shapes are rejected. Very thin shapes may lose floating-point precision.

Why might a rounded result differ?

The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.

Are my inputs saved online?

No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.

Check the assumptions and units before using this result. Read about calculation methods.