Triangle Area Calculator Formula

Understand the math behind the triangle area calculator. Each variable explained with a worked example.

Use the Triangle Area Calculator

Formulas Used

Area

area = 0.5 * base * height

Perimeter Note

perimeter_note = base * height

Variables

VariableDescriptionDefault
baseBase10
heightHeight6

How It Works

How to Calculate Triangle Area

Formula

A = ½ × base × height

Where:

  • base = the length of one side of the triangle
  • height = the perpendicular distance from the base to the opposite vertex

    • This formula works for all triangles — the height must be perpendicular to the base.

    Worked Example

    Find the area of a triangle with base 10 and height 6.

    base = 10height = 6
    1. 01A = ½ × 10 × 6
    2. 02= ½ × 60
    3. 03= 30

    Ready to run the numbers?

    Open Triangle Area Calculator