Triangle from Three Sides
GEOMETRY
Triangle from Three Sides
Find the area of a valid three-sided triangle.
UNDERSTAND YOUR RESULT
How it works
Find the area of a valid three-sided triangle.
THE CALCULATIONarea = √(s(s−a)(s−b)(s−c)); s = perimeter / 2
Using this calculator
Enter first side, second side, third side. area = √(s(s−a)(s−b)(s−c)); s = perimeter / 2.
What to keep in mind
Use the same length unit for all lengths. Areas use squared units and volumes use cubed units. Diagrams are not to scale; inputs must satisfy the shape’s geometry.
Frequently asked questions
Are my entries saved?
No. Calculator inputs remain in the current page and are cleared when you reload or leave. The tools do not upload your entries.
Why are results rounded?
The display is rounded for readability. Calculations use unrounded intermediate values. An estimate should not be interpreted as an exact measurement.