How do I use the Right Triangle Calculator calculator?

Enter your numerical input and select desired units to get instant accurate results.

How accurate are the conversions?

Conversions use official ISO conversion factors for maximum precision.

Yes, seamless conversions between metric (meters, kg) and imperial (feet, lbs) are supported.

No, all calculations execute 100% locally in your browser with zero data logging.

Yes, it provides reliable estimates for construction, crafting, science, and everyday math.

The calculator will display a friendly error prompt if non-numeric values are entered.

Calculated using standard mathematical and industry formulas.

Free online Right Triangle Calculator calculator and unit conversion tool for everyday, engineering, and home projects.

Choose which two values you know: two legs, hypotenuse + one leg, one leg + acute angle, or hypotenuse + acute angle.
Enter those two values in the fields shown.
Read hypotenuse, area, perimeter, both acute angles, and altitude to hypotenuse instantly.
The calculator also checks whether your triangle forms a Pythagorean triple (integer sides).

Pythagorean Theorem & Trigonometry

c = √(a² + b²) · Area = ½ab · sin A = a/c · cos A = b/c · tan A = a/b

Right angle C = 90° always. Angles A + B = 90°. Altitude to hypotenuse h = ab / c.

Legs a = 3, b = 4 → c = √(9 + 16) = 5, Area = ½ × 3 × 4 = 6, Angle A = arcsin(3/5) = 36.87°.

The Pythagorean theorem a² + b² = c² defines every right triangle uniquely once any two sides are known.
Common Pythagorean triples: 3-4-5, 5-12-13, 8-15-17, 7-24-25.
The altitude to the hypotenuse h = ab / c creates two smaller right triangles similar to the original.
Sine, cosine, and tangent are defined from the right triangle: sin A = opposite / hypotenuse = a / c.

The longest side, opposite the 90° angle. Always computed as c = √(a² + b²).

The perpendicular segment from the right angle to the hypotenuse: h = ab / c.

If all three sides are positive integers with a² + b² = c², the triangle is a Pythagorean triple — fundamental in surveying and carpentry.

How do I use the Right Triangle Calculator calculator?: Enter your numerical input and select desired units to get instant accurate results.
How accurate are the conversions?: Conversions use official ISO conversion factors for maximum precision.
Does it convert metric and imperial units?: Yes, seamless conversions between metric (meters, kg) and imperial (feet, lbs) are supported.
Is my data stored?: No, all calculations execute 100% locally in your browser with zero data logging.
Can I use this for DIY or engineering projects?: Yes, it provides reliable estimates for construction, crafting, science, and everyday math.
What if I enter invalid inputs?: The calculator will display a friendly error prompt if non-numeric values are entered.

Triangle Calculator — Solve any triangle from sides or angles using SSS, SAS, ASA, or AAS — area, perimeter, angles and heights.
Area Calculator — Calculate the area and perimeter of rectangles, squares, circles, triangles, trapezoids, ellipses and parallelograms.
Distance Calculator — Calculate distance between two 2D or 3D coordinate points, find the midpoint and slope, or solve speed-distance-time problems.

Note: JavaScript is required for live interactive calculations. Published formulas and reference content remain fully accessible above.