How much carpet do I need?

Multiply the room length by width for the area, add about 10% for trimming and seams, then divide by 9 to convert square feet to square yards. Enter your room size above.

Why is carpet sold by the square yard?

Carpet comes off 12-foot-wide rolls and is traditionally priced per square yard (9 square feet). The calculator gives both units.

How much extra carpet for waste?

Around 10% for a simple room; more for stairs, hallways, or rooms wider than the roll that need seams.

Carpet Calculator

Work out how much carpet you need for a room. Enter the dimensions to get the area in square yards (how carpet is usually sold) and square feet, with a waste allowance.

Carpet calculator

Carpet comes off 12-foot rolls and is usually priced per square yard. Add extra for seams in rooms wider than the roll, and for stairs and hallways.

How it's calculated

We multiply length by width for the floor area, add your waste percentage for seams and trimming, then convert square feet to square yards by dividing by 9.

Frequently asked questions

How much carpet do I need?: Multiply the room length by width for the area, add about 10% for trimming and seams, then divide by 9 to convert square feet to square yards. Enter your room size above.
Why is carpet sold by the square yard?: Carpet comes off 12-foot-wide rolls and is traditionally priced per square yard (9 square feet). The calculator gives both units.
How much extra carpet for waste?: Around 10% for a simple room; more for stairs, hallways, or rooms wider than the roll that need seams.

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<p style="font:12px sans-serif">Carpet calculator by <a href="https://howmanycalc.com/carpet-calculator/">HowManyCalc</a></p>
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Last updated June 2026.