Carpet Calculator
Work out how much carpet a room needs: square yards to buy, linear feet off the roll width in your store, and an optional cost estimate.
How much carpet do I need?
Carpet is priced by the square yard but cut from a roll of fixed width, so there are two honest answers: the area you must buy, and the length of roll that area comes off. Carpet also cannot be stretched around corners — seams, doorways and pattern matching eat material, which is the waste allowance in this calculator.
Square yards = area (sq ft, with waste) ÷ 9 · Roll length = area (with waste) ÷ roll width
Example: a 12 × 15 ft room is 180 sq ft. With a 10% allowance that is 198 sq ft = 22 square yards — 16.5 linear feet off a standard 12 ft roll, and at $30 per square yard, $660 of carpet.
The roll width decides the seams
Most carpet is woven 12 ft wide (13 ft / 4 m and 15 ft rolls exist). If your room is wider than the roll, the installer must seam two pieces together, and seams want to run along the long direction, away from traffic. A room just over roll width — say 12 ft 6 in against a 12 ft roll — is the expensive shape: you buy a second piece for a narrow strip. Check whether a wider roll exists before accepting a seam in the middle of the room.
| Room | Area | Buy (with 10%) |
|---|
| 10 × 12 ft bedroom | 120 sq ft | ≈ 14.7 sq yd |
| 12 × 15 ft living room | 180 sq ft | 22 sq yd |
| 15 × 20 ft great room | 300 sq ft | ≈ 36.7 sq yd |
| Stairs (per step, rough) | ≈ 3 sq ft | Count steps × 3, then add waste |
Closets and hallways count — measure them as their own rectangles with the square footage calculator and add the areas. Underlay (padding) is bought to the same area as the carpet itself, and tack strips run the perimeter of the room; neither changes the square-yard count here.
Frequently asked questions
Why is carpet sold by the square yard but measured in feet?
Tradition — the carpet trade kept the square yard (9 sq ft) as its pricing unit long after rooms started being measured in feet. Stores quote per square yard or per square foot depending on region; this calculator gives both areas so the quotes can be compared honestly.
How much waste should I allow for carpet?
10% suits a plain rectangular room. Seamed rooms, pattern repeats and stairs push it to 15%. The wider the room is compared with the roll, the more the seam cuts cost — that strip down the side is real waste, not installer carelessness.
Does the calculator include the closet and doorway?
Only if their area is in your measurements. Add a closet as its own small rectangle via the square footage calculator and add it to the room area, or type the combined area into the direct-area field here.
Is padding included in the square yards?
No — the count here is carpet only. Padding is bought to the same area (use the same square-yard figure), and your installer will price it as its own line. Skipping new padding under new carpet is false economy; the carpet wears from underneath.
CalcCoverage