Heron's Formula Calculator
Calculate triangle area from three side lengths using Heron's formula, with semiperimeter, triangle inequality checks, heights, angles, and incircle/circumcircle radii.
Triangle area from three sides
The English intent for Heron's formula calculator is narrower than a full triangle solver: users know all three sides and need the area. This page validates triangle inequality, calculates the semiperimeter, and then reports area plus useful verification values.
s is the semiperimeter; a, b, and c are the three side lengths.
A is triangle area by Heron's formula.
Checks and outputs
| Item | Why it matters |
|---|---|
| Triangle inequality | The sum of any two sides must be greater than the third side. |
| Semiperimeter | The intermediate value used in Heron's formula. |
| Very narrow triangle warning | Nearly degenerate triangles can be sensitive to rounding. |
| Heights and angles | Helpful for checking homework or a geometry worksheet. |
When to use another method
Frequently Asked Questions
Sources and References
- Heron's FormulaWolfram MathWorld
- Triangle CalculatorCalculator.net
- Heron's Formula CalculatorEasy Math Tools
Calculations are based on the listed reference sources. Links open in a new tab.
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