Triangle Area Calculator
Calculate a triangle's area from the base and height, or from three side lengths (Heron's formula). Handy for solving math problems — all calculations happen inside your browser.
Enter the values to see the result.
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Area
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Perimeter
How to use
- Choose the calculation method (base·height or three sides).
- Enter the required values.
- The triangle's area is shown in real time.
Frequently asked questions
How do I find the area from the base and height?
The area of a triangle is the base times the height divided by 2: area = base × height ÷ 2.
How do I calculate when I only know the three sides?
If you know the three side lengths, the area is found with Heron's formula. If the three sides cannot form a triangle (the longest side is greater than or equal to the sum of the other two), the area cannot be calculated.
Are the values I enter sent to a server?
No. All calculations happen only inside your browser, and the values you enter are never sent to or stored on any server.