Advanced Triangle Calculator
Calculate area, perimeter, angles, heights, and more for any type of triangle
Triangle Calculator
About Triangles
What is a Triangle?
A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. Triangles can be classified by their sides or by their angles:
By Sides:
- Equilateral Triangle: All three sides are equal, and all three angles are 60°.
- Isosceles Triangle: Two sides are equal, and the angles opposite the equal sides are also equal.
- Scalene Triangle: All sides and all angles are of different measures.
By Angles:
- Acute Triangle: All three angles are less than 90°.
- Right Triangle: One angle is exactly 90°.
- Obtuse Triangle: One angle is greater than 90°.
Triangle Formulas
Our triangle calculator uses the following mathematical formulas:
Area of a Triangle:
- Basic formula: Area = (base × height) / 2
- Heron's formula (when all three sides are known): Area = √[s(s-a)(s-b)(s-c)] where s = (a+b+c)/2 (semi-perimeter)
- SAS formula (two sides and included angle): Area = (1/2) × a × b × sin(C)
Perimeter of a Triangle:
Perimeter = a + b + c
Pythagorean Theorem (for right triangles):
a² + b² = c² (where c is the hypotenuse)
Features
- Calculate area, perimeter, and angles
- Works with all triangle types
- Multiple calculation methods
- Right triangle calculator
- Instant results
- Mobile-friendly design
- No registration required
- Free to use forever
How to Use This Calculator
- Select the calculation method based on what values you know
- Enter the known values in the input fields
- Click "Calculate" button
- View all calculated properties of the triangle
- The calculator will also identify the type of triangle
Tip: You can enter values in any unit (inches, cm, etc.) as long as you're consistent.
Triangle Diagram
Standard triangle notation with sides a, b, c opposite angles A, B, C respectively.