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Carpet Calculator

A carpet calculator works out how much carpet you need for a room — in square yards (how carpet is sold in the US) and square feet — with a waste allowance for the seams and cuts that come off a fixed 12 ft roll width.

Your measurements

Result

Carpet wastes more than hard flooring because it comes off wide rolls and seams must be planned, so the allowance matters. The calculator also lists the pad and install kit, which is most of what actually ships.

How it is calculated

Area × (1 + waste), converted to square yards (÷ 9). Carpet's 12 ft roll width means real rooms need seam planning and extra for cuts, so the waste allowance is higher than for tile or laminate. Pad is bought to the room area.

Steps

Enter the room length and width, or the area.
Use 10% waste for a simple room; 15%+ for stairs, halls or patterned carpet.
Read the square yards to order (and square feet).
Add carpet pad sized to the same area.
Take the room's longest dimension to your retailer — roll width drives seam placement.

Worked example

A 15 × 12 ft room is 180 sq ft; with 10% waste that's ~198 sq ft, or about 22 square yards of carpet.

Common questions

How many square yards of carpet do I need?

Your floor area in square feet, plus waste, divided by 9. The calculator does it and adds a pad estimate.

Why is carpet sold by the square yard?

It comes off 12 ft (and 15 ft) wide rolls; pricing by the square yard is the trade convention. The calculator shows both units.

How much waste for carpet?

10% for a plain rectangular room; 15-20% for stairs, hallways, or a pattern that must be matched at seams.

Do I need carpet pad?

Yes for almost all carpet — it adds comfort and life. Size the pad to the same room area.