Pythagorean Theorem Calculator
NewSolve right triangles — find the missing side, area, perimeter, and angles.
Pythagorean theorem
Pythagorean Theorem Calculator
Solve right triangles — find the missing side, area, perimeter, and angles.
Enter any two sides of a right triangle to solve the missing side, area, perimeter, and acute angles.
Triangle diagram
Area
½ab
Perimeter
a + b + c
Angle opposite a
Measured in degrees
Angle opposite b
Measured in degrees
Frequently Asked Questions
Do I need to leave one triangle side blank?
Yes. The solver expects any two sides and computes the third, or it validates all three if you already know them.
Why did a value disappear after I edited another side?
When the tool auto-fills a missing side, it remembers that field. If you later change a different side, the previous auto-filled field is cleared so the triangle can be solved again from your new inputs.
What errors does it catch before solving?
It rejects non-positive lengths, and if you supply a hypotenuse it must be longer than the other known leg. If all three sides are filled, it also checks that they really form a right triangle.
Does it only give me the missing side?
No. Once the triangle is valid, it also calculates area, perimeter, and both acute angles in degrees.
Why are my results rounded?
Display values are formatted to four decimal places. The validity check still uses the full numeric result with a small tolerance instead of exact text matching.
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