Square Footage Calculator
Add up the square footage of a room or an L-shaped space from up to three rectangles, with square yards, square meters and an optional cost per square foot.
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How to Calculate
Square footage of a rectangle is length × width in feet. For an L-shaped or irregular room, split it into rectangles that do not overlap, measure each one and add them.
Leave unused sections at 0. Divide square feet by 9 for square yards (how carpet is often priced) and multiply by 0.0929 for square meters.
Measure wall to wall at floor level and round each dimension up to the next inch. For materials, add a waste allowance on top of the area this tool gives you.
See our methodology for how every calculator on this site is built.
Worked Example: An L-Shaped Living Room
Most rooms that look awkward on paper are just two rectangles stuck together. Take a living room that measures 14 ft by 12 ft, with a dining nook 8 ft by 6 ft opening off one side. You're pricing flooring at $4.50 per square foot installed.
- Main room: 14 × 12 = 168 ft²
- Nook: 8 × 6 = 48 ft²
- Total: 168 + 48 = 216 ft²
- Square yards: 216 ÷ 9 = 24 yd²
- Square meters: 216 × 0.0929 = 20.07 m²
- Cost: 216 × $4.50 = $972
The trick is where you draw the dividing line. Measure the main room wall to wall, then measure the nook only from the point where it leaves the main room. If you measure the nook from the far wall of the living room, you count the overlap twice.
Converting Between Units
| To convert | Do this | Example (216 ft²) |
|---|---|---|
| ft² to yd² | Divide by 9 | 24 yd² |
| ft² to m² | Multiply by 0.0929 | 20.07 m² |
| in² to ft² | Divide by 144 | 31,104 in² = 216 ft² |
| m² to ft² | Multiply by 10.764 | 20.07 m² = 216 ft² |
| ft² to acres | Divide by 43,560 | 0.005 acres |
Measuring Mistakes That Cost Money
Measuring at the baseboard
Run the tape along the floor, not along the top of the baseboard or at waist height. Walls are rarely plumb, and a room that is 12 ft at the ceiling can be 12 ft 1 in at the floor. When in doubt, round each dimension up to the next inch.
Mixing feet and inches
12 ft 6 in is 12.5 ft, not 12.6 ft. Divide the inches by 12 before you multiply. Six inches is 0.5, three inches is 0.25, nine inches is 0.75.
Forgetting closets and hallways
If the flooring runs into a closet or down a short hall, measure those as their own rectangles and add them in. That is what the third section in the calculator is for.
Ordering the exact area
The area is what you cover, not what you buy. Flooring, tile and carpet all need extra for cuts and seams, usually 5 to 15% depending on the material and the layout. Get the area right here, then add the waste factor in the material calculator.
Tips From the Field
- Sketch the room on paper first and write each measurement on the sketch. It takes two minutes and stops you from mixing up which wall was which.
- For a triangle (an angled corner or bay), measure the base and the height and use base × height ÷ 2.
- Square footage on a real estate listing is usually finished, heated living area measured to the outside of exterior walls. It will not match the sum of the room sizes.
- Carpet in the US is often quoted per square yard. Divide by 9 before you compare against a per-square-foot price.
Rough Cost
Installed prices per square foot vary widely. Very roughly: sheet vinyl $3 to $6, luxury vinyl plank $4 to $8, laminate $4 to $8, carpet $3 to $7, engineered hardwood $7 to $14, and ceramic or porcelain tile $8 to $20. Interior paint labor is often quoted per square foot of floor area too, typically $2 to $6.
Sources
Frequently Asked Questions
How do I calculate square footage of an L-shaped room?
Split it into two rectangles along one of the inside corners, find length × width of each, and add them. Make sure the two pieces do not overlap.
How do I convert inches to square feet?
Multiply length × width in inches and divide by 144. A 30 × 60 inch area is 1,800 in², or 12.5 ft².
How many square feet are in a square yard?
Nine. A square yard is 3 ft × 3 ft.
Do I include closets in room square footage?
For flooring, yes, if the floor runs into them. For real estate listings, closets count toward heated living area but the room size on a listing usually leaves them out.
How do I measure a room with a bay window or angled wall?
Measure the main rectangle first, then treat the bump-out as its own rectangle or a triangle (base × height ÷ 2). For a material order, rounding the odd piece up to a full rectangle is usually close enough.