How do you calculate square footage?
For a rectangular room multiply length by width: a 12 ft × 10 ft room is 120 square feet. For a circle use π × radius², for a triangle use ½ × base × height, and for a trapezoid average the two parallel sides then multiply by the height. Odd-shaped rooms are easiest to handle by splitting them into rectangles and adding the parts.
How do I convert square feet to square metres?
Multiply square feet by 0.092903, or divide by 10.764. So 120 ft² is about 11.15 m². Going the other way, multiply square metres by 10.764. Note this is different from the plain length conversion — area scales with the square of the length factor.
How much extra should I buy for flooring or paint?
Add 5–10% on top of the measured area for straight layouts to cover cuts and offcuts, and 15% or more for diagonal or herringbone patterns. Buying slightly over is cheaper than a second delivery, and leftover material from the same batch is useful for later repairs.
How many square feet are in an acre?
One acre is 43,560 square feet, or about 4,047 square metres. A square yard is 9 square feet. This calculator shows all of these at once so you can move between property listings, landscaping quotes and building plans without re-measuring.
Gross, net or usable area — which does a property listing mean?
Often it does not say, which is why the same flat can appear with two noticeably different figures. Gross internal area measures everything inside the external walls, including internal partitions, stairwells, cupboards and plant rooms. Net internal area strips out the parts you cannot furnish, such as stairs, lift shafts and structural columns. Gross external area includes the thickness of the outer walls themselves. Balconies and integral garages may be counted, excluded, or included at half weighting depending on the standard in use. If the difference matters — for a price per square metre comparison or a lease — ask which measurement standard the figure follows.
How do I measure an irregular or L-shaped room?
Break it into rectangles, calculate each separately, and add the results — an L-shape is two rectangles, a room with a chimney breast is a rectangle minus a small one. Angled bays split into a rectangle plus two triangles, and a curved bay is close enough to a segment of a circle for material ordering. Measure at skirting height rather than across the middle of the room, and take a reading at both ends of each wall: walls are rarely parallel, and older properties can be out by several centimetres. Use the larger of the two readings when ordering, since material can be trimmed but not stretched.