| Shape | Side A | Side B | Side C | Area | Note |
| {y} |
Calculate the Area of a Triangle from Its Three Sides
This tool returns the area or surface of a triangle by computing Heron's formula.
Heron's formula = area of a triangle
Heron's formula calculates the surface of a triangle from the three segments that make up its three sides.
This area calculator uses this formula for the calculation. For reference, the formula is:Area = √(s × (s - a) × (s - b) × (s - c))
where a, b and c are the lengths of the triangle's sides, and s is the semi-perimeter of the triangle, calculated as follows:
s = (a + b + c) / 2
This formula is very useful for calculating the area of a triangle when the side lengths are known, without needing to know the angles or the height of the triangle.
Using the calculator to find the area of a triangle
To find the area of a triangle, type the values of the three sides or segments into the corresponding fields. The calculator computes the area automatically.
Feet, meters, miles ...
The area unit is the square of the sides' unit. For example, a triangle with sides of 5 meters, 4 meters and 6 meters has an area of 9.9216 m². If the unit were kilometers, the surface would be in km².
Save the data and export it
You can save the calculator's data by pressing Save. A table is then generated with the option to export it in CSV or PDF format.
Keyboard shortcuts
m ⇝ Clear
f ⇝ Save
Why use this calculator?
This calculator is useful for students, engineers, architects and anyone who needs to quickly calculate the area of a triangle without doing the math manually. It is also practical for building and construction professionals who need to evaluate the surfaces of triangular plots or structures.