Carpet Calculator
Find how much carpet a room needs in square yards and square feet, with a waste allowance and an optional cost estimate.
Carpet is usually priced by the square yard. A 10% waste factor covers trimming and matching the pile direction across seams.
Enter the room size to find the carpet needed.
How to use the carpet calculator
Enter the room length and width in feet and set a waste factor. The result shows the carpet needed in both square yards and square feet, with the waste already added. To estimate cost, type a price and choose whether it is quoted per square yard or per square foot.
For a room with a closet or an alcove, measure the main floor and add the extra section as its own area. Carpet rolls come in fixed widths, so a fitter may need more than the bare figure to lay it without an awkward seam.
Why carpet is sold by the square yard
Carpet in the US is traditionally priced and sold by the square yard, a holdover from how it comes off the roll. One square yard is nine square feet, so a price that looks high per yard is often reasonable once you convert it to the per-foot figure.
The calculator shows both units so you can compare quotes on the same basis. A 12 by 15 foot room is 180 square feet, which is 20 square yards before waste, the number a flooring store will likely work from.
Why include a waste factor
A 10 percent allowance covers trimming the carpet to the room and squaring up edges that are never perfectly straight. It also leaves a margin for the cuts a fitter makes around doorways, hearths, and built-in furniture.
Patterned carpet needs more, because the pattern has to line up across the width and at seams, which wastes material at every join. For a bold repeat, raise the waste factor above 10 percent to be safe.
Planning around seams
Carpet comes in rolls of a set width, often 12 feet, so a room wider than the roll needs a seam. A good fitter places seams away from doorways and high-traffic paths and keeps the pile running the same direction on both sides so the join disappears.
The pile direction matters for appearance, since carpet looks different depending on how the light catches the fibers. Matching it across a seam is part of why the waste allowance exists, so do not trim the estimate too close.
Frequently asked questions
- How much carpet do I need for a 12x15 room?
- A 12 by 15 foot room is 180 square feet. Adding a 10 percent waste factor brings it to about 198 square feet, which is 22 square yards, the unit most carpet stores price by.
- Why is carpet priced by the square yard?
- It is the traditional unit for carpet sold off a roll. One square yard equals nine square feet, so converting between the two helps you compare a per-yard quote with a per-foot one on equal terms.
- How much extra carpet should I buy?
- A 10 percent waste factor suits a plain carpet, covering trimming and edge cuts. Patterned carpet needs more because the design must align across seams, so raise the allowance for a bold repeat.
- Will my room need a seam?
- Carpet rolls come in fixed widths, often 12 feet, so a room wider than the roll needs a seam. A fitter positions seams away from doorways and keeps the pile direction consistent so the join is hard to see.
- Can I estimate the total cost here?
- Yes. Enter the price and select whether it is per square yard or per square foot. The calculator multiplies it by the carpet area, including the waste factor, to give an estimated total.