Triangle Area
Calculate the area of any triangle from base and height using the formula A = ½ × b × h. Free online geometry calculator with instant results, formula breakdown, and regional unit support.
About This Calculator
This free triangle area calculator computes the area of any triangle using the classic base and height formula. Whether you are a student learning geometry, a DIY enthusiast measuring materials, or a professional in construction, architecture, or landscaping, this tool provides instant, accurate results for triangle area calculations.
The formula for triangle area is A = \u00bd \u00d7 base \u00d7 height, where the base is any side of the triangle, and the height is the perpendicular distance from the opposite vertex to that base. This formula works for all types of triangles -- right, isosceles, equilateral, and scalene -- as long as you know the base and the perpendicular height. For right triangles, the two legs are naturally perpendicular, making the calculation even more straightforward. For example, a triangle with a base of 10 units and a height of 5 units has an area of A = 0.5 \u00d7 10 \u00d7 5 = 25 square units.
Regional Notes: This calculator works with any consistent measurement system. In the United States, common units include inches, feet, and yards for construction and carpentry projects. In India and the United Kingdom, metric units such as centimeters and meters are standard in school geometry and professional contexts. The result displays in square units matching your input -- whether cm\u00b2, m\u00b2, in\u00b2, or ft\u00b2.
Frequently Asked Questions
How do you calculate the area of a triangle?
The area of a triangle is calculated using the formula A = \u00bd \u00d7 base \u00d7 height. Simply multiply the base length by the height and divide by two to get the area in square units.
What units should I use for the base and height?
You can use any consistent unit such as centimeters, meters, inches, or feet. The area will be displayed in the corresponding square units (cm\u00b2, m\u00b2, in\u00b2, ft\u00b2).
Can this calculator handle decimal measurements?
Yes, the calculator accepts decimal values for both base and height. Enter values like 7.5 or 12.25 to get precise area calculations.
What if I know the three sides instead of base and height?
If you know all three sides, use Heron's formula: A = \u221a(s(s-a)(s-b)(s-c)) where s is half the perimeter. Try our 3 Sides Triangle Area calculator for that method.
Is this tool free to use?
Yes, all calculators on Calculy are completely free to use with no registration required. You can calculate triangle areas as many times as you need.
Can I calculate the area of an equilateral triangle with this?
Yes, enter the side length as the base and the height of the equilateral triangle (which you can find using h = s \u00d7 \u221a3 / 2). For direct equilateral area calculation, try our dedicated Equilateral Triangle Area Calculator.
What is the base and height in a triangle?
The base is any side of the triangle you choose. The height is the perpendicular distance from the opposite vertex to that base. For right triangles, the two perpendicular legs serve as the base and height.
Why is the triangle area formula multiplied by half?
The half factor comes from the fact that a triangle is exactly half of a parallelogram or rectangle with the same base and height. If you take a rectangle of base b and height h, its area is b \u00d7 h, and a triangle with the same dimensions fills exactly half of it.