How Do I Calculate Square Feet? (Rooms and Houses)
Measure the length and the width of the room in feet, multiply them to get the floor area, add the areas of every room, and round the total once at the end; the steps below work one example for each part.
Estimates for planning, not professional advice. Read the full notice.
Work it out for your own sizes
Try your own room sizesStep by step
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Step 1: Measure the length and width
Measure along the floor from wall to wall with a tape, once for the length and once for the width. In this example the living room is 14 ft long and 11 ft wide.
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Step 2: Multiply length by width
Multiply the length by the width: 14 ft times 11 ft gives 154 ft².
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Step 3: Add the rooms, round once
Work out each room the same way, add the exact areas, and round only the total. The living room, 154 ft², the bedroom, 130 ft² and the hall, 32 ft² add to 316 ft², rounded once at the end.
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Step 4: Read feet and inches
A size such as 9 ft 4 in by 13 ft 8 in is multiplied exactly, with the inches kept as fractions of a foot, and gives 127.56 ft². Rounding each size to whole feet first would change the answer.
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Step 5: Split an odd shape into rectangles
Split an L or any other shape into rectangles, find each area and add them. A main part of 10 ft × 16 ft gives 160 ft² and a bump of 4 ft × 6 ft gives 24 ft², which add to 184 ft².
Questions
How do I calculate the square feet of a room?
Measure the length and the width in feet and multiply them. The result is the floor area in square feet, and it is not rounded until the final total.
How do I calculate square feet when the room has an alcove or a bump?
Measure the main part and the alcove as separate rectangles, work out each area and add them. The same split works for any room made of straight walls.
Do I measure to the wall or to the baseboard?
Measure the floor along the wall surface you are counting, and use the same choice for every room so the totals can be added. Say which one you used next to the figure.
How do I work out the square feet of a whole house?
Work out each room's floor area, add the exact areas and round the total once. Rooms that repeat can be counted by their number of copies.
Do I include closets and hallways?
Add them as rooms of their own when you want the whole floor, and leave them out when you only want the area of one room. The method is the same for both.
Calculate it for your project
Enter your own sizes to get the amount to buy or the layout figures, with the working shown and a page to print.
Add up your rooms here