Solve triangle area, perimeter, missing sides, angles, and triangle type with this free triangle calculator.
Area from base and height:
A = 1/2 × b × h
Perimeter:
P = a + b + c
Heron's formula:
A = √(s(s-a)(s-b)(s-c))
Pythagorean theorem:
c² = a² + b²
Triangles are used in geometry, construction, engineering, design, and trigonometry. They are one of the most important shapes in measurement and problem solving.
Understanding side lengths, angles, and area helps with layouts, slopes, distances, and structures.
Your result shows the area, perimeter, side lengths, angles, and triangle type based on the mode and dimensions entered.
This makes it easier to identify the triangle and understand how its measurements relate.
Heron's formula finds triangle area from all three sides using A = √(s(s-a)(s-b)(s-c)).
A right triangle has one angle equal to 90 degrees.
Triangles are classified by side length or angle, such as equilateral, isosceles, scalene, or right.
No. The sum of any two sides must be greater than the third side.