Carpet Calculator

About this calculator

Carpet is manufactured and sold in long rolls of a fixed width (commonly 12 feet or 4 metres), so buying carpet for a rectangular room isn't as simple as multiplying floor area. You need to work out how many linear metres of that fixed-width roll must be cut to fully cover the room, and because a roll's width rarely divides the room's dimensions evenly, some cutting waste is almost always unavoidable.

Installers and homeowners use this kind of calculation to get an accurate materials estimate before ordering, since underestimating carpet means a delayed second order (and possible dye-lot mismatches between batches), while overestimating means paying for material that ends up as offcuts. The waste factor grows with room shapes that don't align neatly with the roll orientation, alcoves, and any pattern that needs to be matched at seams.

Enter your room's dimensions and the roll width, and this calculator returns the floor area, the linear metres to buy, and the expected cutting waste.