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Floor area calculator, room by room

Enter each room’s length and width from the plan or a tape measure. The total updates as you type, in sq ft.

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    How the floor area is worked out

    Each room is length × width, measured from the inside face of one wall to the inside face of the opposite one. Add the rooms together and you have the apartment’s internal floor area, the figure most floor plans write inside each room and the one to compare between apartments.

    Rooms that aren’t rectangles are split: an L-shaped living room is two rectangles, a room with a chimney breast is the full rectangle minus the breast. Enter each part as its own row.

    Listings often quote a larger gross figure measured over the walls, or one that includes balconies or common parts. For the definitions and how to check a listing’s number, see how to measure floor area; for what each room usually measures, standard room sizes.

    Questions, answered

    How do I calculate the floor area of a room?

    Multiply its length by its width, both measured wall to wall: a room 13 ft by 11 ft 6 in is 150 sq ft. For an L-shaped room, split it into two rectangles, work out each and add them.

    How do I calculate the floor area of an apartment from its plan?

    Read each room’s length and width from the plan’s dimension lines, enter them here as one row per room, and the total is the apartment’s usable floor area. Measured over the walls instead, the same apartment typically comes out 5–10% larger: that is the gross figure many listings quote.

    How many square feet is 10 square feet?

    11 sq ft is 10.764 sq ft, and 1 sq ft is 1 sq ft. So a 540 sq ft apartment is 538 sq ft, and a 1,000 sq ft apartment is 1,000 sq ft.

    Do balconies count in the floor area?

    Usually not in the internal area: UK and Polish rules leave them out, and plans list them separately. Some markets, Dubai among them, include them in a saleable area, so check which figure a listing gives.

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