Triangle Calculator

Calculate and generate basic info for any triangle for free!

This tool will calculate the type, area, perimeter, height, and median of any triangle.
Side A =
Side B =
Side C =
Angle A =
Angle B =
Angle C =

How to Find Triangle Properties Using our Triangle Calculator

  1. Input Your Values - Enter three values, which can be a combination of sides and angles. Ensure they describe a valid triangle, it does not have to be a right triangle.
  2. Review the Results - Our calculator processes the inputs and displays all the triangle properties, such as; Triangle type, side lengths, angles, area, perimeter, semiperimeter, height, medians, inradius, and circumradius.
  3. Find Your Answer - Look for the triangle property you wanted to calculate in the results

Tips for Accurate Results:

  • Make sure you have 3 data values entered into the calcualtor above.
  • Ensure the sum of angles does not exceed 180 degrees.
  • At least one side must be entered.
  • For side inputs, the sum of any two sides should be greater than the third.
  • Double-check your inputs for any typographical errors.

How to Calculate Each of These Triangle Properties on Your Own

Triangle Type:

  • By Angles: You can classify triangles based on their angles as shown below.
    • Acute Triangle: All angles are less than 90 degrees.
    • Right Triangle: One angle is exactly 90 degrees.
    • Obtuse Triangle: One angle is more than 90 degrees.
  • By Sides: You can classify triangles based on their sides as shown below.
    • Equilateral Triangle: All sides are equal.
    • Isosceles Triangle: Two sides are equal.
    • Scalene Triangle: All sides are of different lengths.

Side Lengths & Angles:

  • Pythagorean Theorem: Useful for finding the missing side of a right Triangle.

    For missing side use A^2 + B^2 = C^2 with C being the hypotenuse.

  • Law of Cosines: Useful for finding a side when two sides and an angle in-between are known, or an angle when all sides are known.
  • Law of Sines: Useful when the lengths of two sides and a non-included angle are known, or two angles and any side.


  • Heron's Formula: Use to find area when you know all three sides.
  • For Right-Angled Triangles: Area = b*h / 2

Perimeter & Semiperimeter:

  • Perimeter: Add up the lengths of all three sides.
  • Semiperimeter: Half of the total perimeter, used in various formulas.


  • The height is the perpendicular distance from a vertex to the opposite side.

    Use the area formula and solve for Height = 2*Area/base.


  • A median connects a vertex to the midpoint of the opposite side.

Inradius & Circumradius:

  • Inradius: The radius of the inscribed circle within the triangle.
  • Circumradius: The radius of the circumscribed circle around the triangle.

Good luck, and dont forget to bookmark this triangle property calculator to save time when you need quick info on a non right triangle