Practical AtlasIndependent referenceFree online tool
Square footage calculator
Work out the square footage of a room, circle, or triangle, add up an L-shaped floor plan, and turn the total into a flooring or paint cost.
Calculate square footage.
Measure a rectangle, circle, or triangle in feet and turn the area into a material or flooring cost when you have a price.
COMMON WAYS TO ASK
- How many square feet is a 12x12 room?
- How do I calculate square footage?
- How much flooring do I need for a room?
What this calculator tells you.
Choose a shape, enter its measurements in feet, and read the area in square feet. Add a price per square foot to turn the area into a quick material-cost estimate.
A 12 × 15 ft room with flooring at $3.50
Questions people ask next.
How many square feet is a 12x12 room?
A 12 by 12 foot room is 144 square feet, because square footage is the two side lengths multiplied together. The same rule gives 100 square feet for 10 by 10, 400 for 20 by 20, and 1,200 for 30 by 40.
How do I measure an L-shaped room?
Split it into two rectangles at the inside corner, calculate each area, and add them. Complex floor plans are always sums of simple shapes.
Should I add extra material beyond the area?
Usually yes. Cuts, pattern matching, and mistakes consume material, so flooring and tile orders commonly add around 5 to 10 percent waste. The room finish estimator handles that explicitly.