Heron's Formula Calculator
Calculate the area of a triangle using Heron's formula. Input the lengths of all three sides.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Heron's Formula Calculator
- Enter side lengths: Type the lengths of the three sides (A, B, C) into the input fields. Use any positive number (e.g., 5, 6.5, 7). The calculator works with any unit (inches, cm, meters) as long as all sides use the same unit.
- Click "Calculate Area": Press the blue button to compute the area.
- Check the result: The area appears in green, followed by step-by-step calculations showing the semi-perimeter and the formula.
- If you see an error:
- Red borders mean a side is missing or not a positive number.
- A red alert means the sides don't form a triangle (e.g., 1, 2, 100). Ensure each pair of sides sums to more than the third side.
Tip: Use the same unit for all sides (e.g., all in meters). The result will be in square units (e.g., m²).
Previous Results
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Frequently Asked Questions
Heron's formula calculates the area of a triangle when the lengths of all three sides are known. It is area = √[s(s-a)(s-b)(s-c)], where s is the semi-perimeter.
Yes, as long as the side lengths satisfy the triangle inequality theorem (sum of any two sides greater than the third).
The area is given in square units consistent with the input units. For example, if sides are in meters, area is in square meters.
