How to use the square footage calculator
- Choose whether you measured in feet or meters.
- Pick the shape of the area: rectangle (most rooms), circle or triangle.
- Enter the measurements. For a rectangle, that's the length and width.
- Optionally add extra for waste and a price per square foot to estimate the cost of flooring, paint or other materials.
Square footage formulas
If your measurements are in inches, divide by 12 to get feet first — or calculate square inches and divide by 144 (12 × 12) to get square feet.
Example
A bedroom that measures 12 ft × 15 ft has an area of 12 × 15 = 180 square feet (about 16.72 m² or 20 square yards). If you're installing flooring and add 10% for cuts and waste, buy material for 198 sq ft. At $4.50 per square foot, that's about $891.
Measuring irregular rooms
For an L-shaped room or an open-plan space, split the floor into rectangles, calculate each one and add them together. For example, an L-shaped room made of a 12 × 15 ft section and an 8 × 10 ft section is 180 + 80 = 260 square feet. Subtract areas you won't cover, such as a kitchen island.
How much extra flooring should I buy?
- 5% — simple rectangular rooms with straight-lay planks or carpet.
- 10% — the standard allowance for most tile, laminate and hardwood.
- 15% or more — diagonal layouts, herringbone patterns or rooms with many corners.
Keeping a few spare boxes also makes future repairs easier, since the same batch can be hard to find later.
Square feet vs. square meters
One square meter equals about 10.764 square feet, and one square foot is about 0.0929 m². Use the square feet to square meters converter for quick conversions.
Frequently asked questions
How do I calculate square footage of a room?
Measure the length and width of the room in feet and multiply them. A 10 ft by 12 ft room is 120 square feet.
How do I calculate square feet from inches?
Multiply the length and width in inches to get square inches, then divide by 144. For example, 120 in × 96 in = 11,520 sq in ÷ 144 = 80 sq ft.
How many square feet is a 12x12 room?
A 12 by 12 foot room is 144 square feet.
How do I find the square footage of a house?
Measure each room (or each rectangular section of the floor plan), calculate their areas and add them together. Listings usually count finished, heated living space and exclude garages and unfinished basements.
Should I add extra for waste?
Yes, for most materials. Add about 10% for tile, laminate or hardwood flooring, and 15% or more for diagonal or patterned layouts.
Results are provided for convenience and rounded for display. Sales tax rules, tipping customs and date conventions differ by location, so check local rules when it matters.
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