How to calculate square footage of a room
How to calculate square footage: multiply the length by the width in feet, so a 12 by 15 ft room is 180 sq ft. Plus L-shaped rooms and flooring.
By the Tapepal teamUpdated 5 min read
Short answer
180 sq ft for a 12 by 15 ft room: measure the length and the width in feet and multiply them. Split odd shapes into rectangles and add them up.
How do you measure a rectangular room?
Measure two walls that meet in a corner, in feet, and multiply.
- Measure the length Wall to wall along the longest side, in feet.
- Measure the width Wall to wall the other way.
- Multiply 12 ft × 15 ft = 180 sq ft.
How do you find the square footage of a room that isn’t square?
Split it into rectangles, work out each one, and add the areas. Draw the room roughly on paper first, then measure each rectangle. The L-shaped room below is 35 + 96 = 131 sq ft.
How do you convert inches, feet and square yards?
Turn inches into feet before you multiply, then divide square feet by 9 for square yards.
| If you have | Do this |
|---|---|
| Feet and inches | Turn inches into feet: 6 in = 0.5 ft |
| Square inches to sq ft | Divide by 144 |
| Square feet to square yards | Divide by 9 |
How much flooring should you buy?
Add 10% for cuts and mistakes, or 15% for diagonal layouts. For 131 sq ft, buy about 144 sq ft.
Can you get the floor plan instead?
265 sq ft, with every wall. Tapepal draws the plan as you walk the room. Needs an iPhone with LiDAR.
Questions
Do I include closets?
For flooring, yes, if the floor continues into them. For heating or listings, follow the rules you are working to.
How do I measure a room with a bay window?
Measure the main rectangle, then the bay as its own rectangle or half-circle, and add them.
How many square feet in a square yard?
Nine. A square yard is 3 ft × 3 ft, and carpet is often priced by the square yard.
How many square feet is a 12 × 12 room?
144 sq ft. Multiply 12 ft by 12 ft.
What size is a 300 sq ft room?
For example 15 × 20 ft, or 12 × 25 ft. Any length and width that multiply to 300 make 300 sq ft.
Does ceiling height change the square footage?
No. Square footage is the floor only, length × width. Height matters for the wall area, when you work out paint.
How we checked this. Area is length × width. 1 sq yd = 9 sq ft and 1 sq ft = 144 sq in. The flooring extra follows common installer advice: 10% for straight layouts, 15% for diagonal ones. Reviewed by the Tapepal team on .
