Heron's formula calculator

Given the three lengths of any triangle, Heron's formula calculator will compute the area for you.

Instructions for using the Heron's formula calculator

Note that the triangle above is only a representation of a triangle.

Your triangle may look different. However, all it takes to find the area is to enter the lengths of a, b, and c.

If the area = 0, this means that the lengths you entered gave a straight line instead of a triangle.

This happens when the length of one side (the longest side) equal to the sum of the other two sides.

If it says NaN, the values you entered did not make a triangle.

You make a triangle when the length of any side is smaller than the sum of the other two sides.

Examples showing how to use the Heron's formula calculator.

Example #1:

Find the area of a scalene triangle if the lengths of the three sides are 10, 8, and 9.

Enter 10 in the box labeled " Enter the length of a "  

Enter 8 in the box labeled " Enter the length of b "

Enter 9 in the box labeled " Enter the length of c "  

Click the button that says "Calculate"

The calculator should display 34.197039345533994

Example #2:

Find the area of a scalene triangle if the lengths of the three sides are 5, 4 and 4.5.

Enter 5 in the box labeled " Enter the length of a "  

Enter 4 in the box labeled " Enter the length of b "

Enter  4.5 in the box labeled " Enter the length of c "  

Click the button that says "Calculate"

The calculator should display 8.549259836383499

Example #3:

Find the area of a right triangle if the lengths of the three sides are 4, 5 and 3.

Enter 3 in the box labeled " Enter the length of a "  

Enter 5 in the box labeled " Enter the length of b "

Enter  4 in the box labeled " Enter the length of c "  

Click the button that says "Calculate"

The calculator should display 6.

Does this result surprise you? Well, it should not. Since we are dealing with a right triangle, the hypotenuse is the longest or 5. This means that the base is either 3 or 4.

Area = (4 times 3)/2 = 12/2 = 6