How to Calculate Triangle Area: Formula & Easy Examples

The area of a triangle is the total space inside the triangle. It is a basic formula used in construction, design, and math education.

Triangle Area Formula

Area = ½ × base × height

• Base = the length of the side used as the base
• Height = the perpendicular distance from the base to the opposite vertex

Example

A triangle with a base of 10 cm and a height of 6 cm:

• Area = ½ × 10 × 6 = 30 square centimeters (cm²)

When You Know All Three Sides (Heron’s Formula)

If you know the three sides a, b, c but not the height, use Heron’s formula:

1. s = (a + b + c) ÷ 2
2. Area = √(s × (s − a) × (s − b) × (s − c))

Example: sides 5, 6, 7 cm → s = 9 → Area = √(9×4×3×2) = √216 ≈ 14.7 cm²

Area Units

• Square centimeters (cm²) for small shapes
• Square meters (m²) for construction and land

Real-World Uses

• Roof or wall areas with triangular shapes
• Tiling sloped floors
• Math classes and exams

Try the triangle area calculator to get instant results without manual math.