📐 Area of a Triangle Calculator
Pick a method, enter your measurements, and instantly find the area of your triangle.
What this calculator does
This tool finds the area of a triangle using whichever measurements you have on hand: a base and height, or all three side lengths.
The formulas used
With a base and height, area is calculated as Area = ½ × base × height, where the height is the perpendicular distance from the base to the opposite corner. With three side lengths, the calculator uses Heron’s formula: Area = √(s(s-a)(s-b)(s-c)), where s is the semi-perimeter (half the sum of all three sides).
Good to know
When using the three-sides method, the calculator checks that the three lengths can actually form a triangle (each side must be shorter than the sum of the other two) before computing an area. This tool is intended for general educational and planning purposes, such as school geometry or basic construction estimates.