Construction

Square Footage Calculator

Calculate the square footage (area) of any rectangular, triangular, or circular space. Results also shown in square meters and square yards.

Select a shape and enter dimensions to calculate the area.

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Area Formulas by Shape

Rectangle

A = L × W

L = length, W = width

Triangle

A = ½ × B × H

B = base, H = height

Circle

A = π × r²

r = diameter ÷ 2

When You Need Square Footage

Square footage is the standard area measurement for residential and commercial real estate in the United States. It is used to calculate flooring, paint, carpet, tile, sod, and insulation quantities, as well as to determine heating and cooling loads in HVAC planning.

When buying materials, always add a 10–15% overage to account for waste, cuts, and future repairs. For irregularly shaped rooms, break the space into smaller rectangles or triangles, calculate each section separately, and sum the totals.

Frequently asked questions

How do I calculate square footage?
For a rectangle, multiply length by width: Area = Length × Width. For a triangle, use Area = 0.5 × Base × Height. For a circle, use Area = π × radius², or equivalently π × (diameter / 2)². All measurements should be in feet to get square feet. This calculator handles all three shapes automatically.
How many square feet is a 10×10 room?
A 10-foot by 10-foot room is exactly 100 square feet (10 × 10 = 100). This is a common reference size used in real estate listings and storage unit descriptions. A typical bedroom in the US is 120–200 square feet, and a standard one-car garage is about 200–240 square feet.
How do I convert square feet to square meters?
Multiply square feet by 0.0929 to convert to square meters. One square meter equals approximately 10.764 square feet. For example, a 500 square foot apartment is about 46.5 square meters (500 × 0.0929). This conversion is frequently needed when dealing with international real estate or metric-system building materials.
How much square footage do I need for flooring?
Measure the total square footage of the rooms to be floored, then add 10–15% for waste and cutting errors. For example, a 200 square foot room needs about 220–230 square feet of flooring material. Complex room shapes with many cuts, diagonal installations, or large format tiles require a higher waste allowance of up to 20%.
What is a square yard and how does it relate to square feet?
One square yard equals 9 square feet, because 1 yard = 3 feet and area scales by the square (3 × 3 = 9). Carpet is commonly sold by the square yard, so dividing your square footage by 9 gives you the amount of carpet needed. For example, 180 square feet of flooring equals 20 square yards.

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