Room Area Calculator

A room area calculator multiplies a room's length by its width to give the floor area, and converts that figure between square feet and square metres.

This calculator turns two measurements — the length and width of a rectangular room — into the numbers a supplier will ask for: floor area in square feet and square metres, the perimeter for skirting or coving, and how much flooring to order once cutting wastage is allowed for. It is the measurement people need most often when pricing tiles, carpet, vinyl or laminate.

1. Measure the room at floor level, wall to wall, and take the longest span as the length.
2. Enter the length and width, then pick the unit you measured in.
3. Adjust the wastage allowance if your layout needs more than the usual 10%.
4. Read the floor area and the quantity to buy, and copy the result to send to a supplier.

area      = length × width
perimeter = 2 × (length + width)
to buy    = area × (1 + wastage ÷ 100)

Both measurements are converted to metres before they are multiplied, so mixing units is never a problem. One square metre is 10.7639 square feet; the calculator shows both because Indian suppliers quote in either.

A bedroom measured at 12 ft by 10 ft, tiled with a straight layout.

Order flooring for 132 sq ft. If the tiles come in boxes covering 15 sq ft, that is 9 boxes with a little left over for future repairs.

• The area includes the space under skirting, because flooring normally runs beneath it. Fitted units usually do not count — measure them separately and subtract.
• Large-format tiles, diagonal layouts and herringbone patterns waste more than 10%. Allow 15% or more for those.