Classic tool
Pythagoras Diagonal Calculator
Calculate the diagonal of a right triangle, check square, area and angles.
The Pythagoras Diagonal Calculator applies the Pythagorean theorem to find the hypotenuse (the longest side, opposite the 90° angle) of a right triangle, to check if three measurements form a valid triangle, and to compute the area, perimeter and the two acute angles.
To use it, fill in at least two of the three sides: A, B (legs) and C (hypotenuse). If you provide all three, the tool checks the Pythagorean relation; if you provide two, it computes the third. The result shows the hypotenuse, area, perimeter and the angles in degrees, and renders the triangle in SVG for visualisation.
Use the result to check the squareness of furniture, calculate the diagonal of a rectangular piece, find the slope of a ramp or solve any carpentry and construction problem that involves right triangles.
Use clear inputs to get a more useful result.