How carpet is measured
Carpet is often priced by the square yard and cut from rolls that are usually 12 feet wide. That means two numbers matter: how much area you're covering, and how much roll length the installer has to cut to cover it.
The calculator gives you both. It finds your room area, adds waste, converts to square yards, and works out the shortest length you can cut from the roll, checking both directions.
Example: a 15 × 12 bedroom
- Area: 180 sq ft, or 20 sq yd
- Add 10%: 22 sq yd
- The room is 12 ft wide, so one 15 ft cut from a 12 ft roll covers it with no seam
Seams and pile direction
When a room is wider than the roll, you need a seam. Installers try to put seams away from doorways and heavy traffic, and all the pieces have to run in the same pile direction or the color looks different. That's why the cut length can be more than the room's area suggests.
Before you buy
- Measure into doorways to the middle of the door when it's closed.
- Include closets if they're getting carpet.
- Order pad for the room area. It's usually sold by the square yard too.
- Let the installer do a final measure before you order. Most stores offer it.
Planning hard flooring for another room? Use the flooring calculator.
Frequently asked questions
How do I calculate square yards of carpet?
Multiply the room length by the width in feet, then divide by 9. A 12 by 15 room is 180 square feet, or 20 square yards.
How much extra carpet should I buy?
About 10 percent for a simple room and 15 percent for rooms with odd angles, closets or stairs.
How wide is a roll of carpet?
Most carpet comes in 12-foot-wide rolls. Some styles come in 13 feet 6 inches or 15 feet.
How much carpet do I need for a 12x12 room?
144 square feet, or 16 square yards, plus about 10 percent waste, so roughly 17.6 square yards.
Results are estimates for planning. Product coverage, site conditions and installation methods vary, so check manufacturer guidance before you buy.