Heron's formula calculator

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

A-triangle-image

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.


Enter the length of a:        

Enter the length of b:        

Enter the length of c:       







The area is :   



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

 Buy a comprehensive geometric formulas ebook. All geometric formulas are explained with well selected word  problems.

Recent Articles

  1. Factoring trinomials of the form x^2 + bx + c

    Jul 03, 20 09:51 AM

    factoring trinomials (ax^2 + bx + c ) when a is equal to 1 is the goal of this lesson.

    Read More

New math lessons

Your email is safe with us. We will only use it to inform you about new math lessons.

                                 Follow me on Pinterest

Real Life Math Skills

Learn about investing money, budgeting your money, paying taxes, mortgage loans, and even the math involved in playing baseball.