Carpet Calculator — Free Online Tool
Carpet is priced and sold by the square yard, but rooms are measured in feet — and that conversion trips up nearly every first-time buyer. This carpet calculator does it instantly, with extra built in for cuts and seam direction.
What is the Carpet Calculator?
One square yard equals 9 square feet, so a 12×15 room (180 sq ft) needs 20 square yards before waste. The extra 10% matters more with carpet than most materials because seams must run in the same direction (the “nap”) or they show as visible stripes — installers need cutting room to keep every piece oriented correctly.
Measure each room separately and add closets you want carpeted — they're easy to forget and annoying to piece in later. If your carpet has a pattern, bump waste toward 15% so motifs align at seams. This carpet calculator includes a 10% cutting allowance by default; share the room dimensions with your installer too, since they'll plan seam placement around doors and traffic paths.
How to use this calculator
- Measure each room's length and width in feet.
- Include closets you want carpeted.
- Enter the dimensions and click Calculate Carpet.
- Confirm seam layout with your installer before ordering.
Formula
Frequently asked questions
Why is carpet sold in square yards?
It's the industry standard — carpet rolls are 12 feet wide and priced per square yard (9 sq ft). This carpet calculator handles the conversion.
How much extra carpet do stairs need?
Measure stairs separately: tread depth plus riser height per step, plus a few inches per step for wrapping the nosing.
Does the price include padding?
No — carpet pad is sold separately, also by the square yard. Don't skip it; pad doubles carpet life.
What about patterned carpet?
Patterns must align at seams, which wastes material — plan on ~15% extra instead of 10%.