Free Square Feet of a Triangle Calculator

Understanding Triangle Square Footage Calculation

Whether you are laying flooring, estimating land area, or solving a geometry problem, knowing how to calculate the square feet of a triangle is essential. Our triangle square footage calculator accepts multiple input formats, making it a versatile triangle area calculator square feet tool. Choose the combination of measurements you already have — such as base & height, three sides (SSS), side‑angle‑side (SAS), or angle‑side‑angle (ASA) — and the tool instantly returns the sqft of the triangle.

For those who prefer to work manually, the formulas behind the calculator are straightforward. Below we walk through each common case.

Base and Height

If you know the base $b$ and the height $h$ perpendicular to that base, the triangle square feet formula is:

$$A = \dfrac{1}{2} \times b \times h$$

Simply multiply the base by the height and then take half of that product.

Three Sides (SSS) — Heron’s Formula

When all three side lengths $a$, $b$, and $c$ are known, first compute the semiperimeter:

$$s = \dfrac{a + b + c}{2}$$

Then apply Heron’s formula:

$$A = \sqrt{s\,(s-a)\,(s-b)\,(s-c)}$$

The result is the area in square feet (assuming all sides are measured in feet).

Side‑Angle‑Side (SAS)

When you have two sides $a$ and $b$ and the included angle $\gamma$, use:

$$A = \dfrac{1}{2}ab\,\sin\gamma$$

Ensure the angle is in degrees (the calculator handles the conversion automatically).

Angle‑Side‑Angle (ASA)

With two angles $\beta$ and $\gamma$ and the side $a$ between them, the area can be found with:

$$A = \dfrac{a^{2} \sin\beta \sin\gamma}{2\sin(\beta+\gamma)}$$

This formula derives from the law of sines and works for any unit of measurement.

As you can see, the core triangle square feet formula depends only on the information you have. Whether you use the digital square feet of triangle calculator or compute by hand, the result is the same.