Geometry & Measurement Calculators
Triangle Area Calculator
Find the area of a triangle from base and height, three sides (Heron's formula), or two sides and an angle.
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What is Triangle Area?
The area of a triangle has several exact formulas depending on what you know. Base-and-height is the simplest; Heron's formula works from three sides alone; the SAS form uses two sides and the included angle.
How it works
We validate the inputs (including the triangle inequality), apply the formula for the method you picked, and show the substitution alongside the result.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.