Area Calculator

How to use the area calculator

1. Choose the shape you are measuring.
2. Pick the unit your measurements are in.
3. Enter the measurements. The area appears in your unit and is converted to square feet, square meters, acres and hectares.

For an L-shaped room or yard, split it into rectangles, find each area, and add them together.

Area formulas

Shape	Formula	What the letters mean
Rectangle	A = l × w	length and width
Square	A = s²	side length
Triangle	A = ½ × b × h	base and perpendicular height
Triangle (3 sides)	A = √(s(s−a)(s−b)(s−c))	s = half the perimeter (Heron's formula)
Circle	A = πr²	radius
Sector	A = (θ/360) × πr²	angle in degrees and radius
Trapezoid	A = ½ × (a + b) × h	the two parallel sides and the height
Parallelogram	A = b × h	base and perpendicular height
Ellipse	A = π × a × b	the two semi-axes

Worked example

A room 12 ft long and 10 ft wide has an area of 12 × 10 = 120 ft², which is 11.15 m² or 13.33 square yards.

Converting square units

Area units convert by the square of the length conversion. There are 12 inches in a foot, so there are 12 × 12 = 144 square inches in a square foot. Some useful values:

• 1 square yard = 9 square feet
• 1 square meter = 10.764 square feet
• 1 acre = 43,560 square feet
• 1 hectare = 10,000 square meters = 2.471 acres

Frequently asked questions

How do I calculate square footage?

Measure the length and width in feet and multiply them. A 15 ft by 20 ft room is 300 square feet. For other shapes, choose the shape in the calculator.

What is the difference between area and perimeter?

Area is the space inside a shape, measured in square units. Perimeter is the distance around the edge, measured in ordinary length units.

How do I find the area of a triangle without the height?

Choose "Triangle (3 sides)". It uses Heron's formula, which needs only the three side lengths.

How many square feet are in an acre?

One acre is 43,560 square feet, or about 4,047 square meters.

Can I mix units, like feet and inches?

Convert everything to one unit first. For example, 10 ft 6 in is 10.5 ft.