Carpet Calculator

How carpet quantities are calculated

You don't buy carpet by the room — you buy a length cut off a roll of fixed width (usually 12 ft, sometimes 15 ft). So the math works in cuts:

Cuts across the room = room width ÷ roll width, rounded up
Linear feet = cuts × room length
Square yards purchased = linear feet × roll width ÷ 9

Because the pile must run the same direction in every piece, this calculator lays the room out both ways — roll running along the length, then along the width — and uses whichever buys less carpet. The waste allowance then extends the cut length (rounded up to whole feet) to cover trimming, seam placement, and closets or alcoves your rectangle measurement missed. If the room is wider than the roll, there will be seams: the "cuts" figure tells you how many roll-width pieces the installer will join.

Why square yards paid ≠ room size: if your room is 14 × 12 ft (18.7 sq yd of floor) and the roll is 12 ft wide, one 14-ft cut covers it — but at a 10% waste allowance you order 16 linear feet, which is 21.3 sq yd of carpet. The difference is the price of roll goods; choosing a 15 ft roll, or flipping the layout, sometimes shrinks it. Patterned carpet needs the higher allowance (and sometimes extra length per cut to match the repeat) — confirm with your installer before ordering.