How the carpet calculator works
Broadloom carpet comes off a roll, so the room is covered in full-width strips laid along its length. If the room is wider than the roll, you need a second run and a seam. Any width beyond the room becomes an offcut you still pay for.
The chart separates the floor itself, the roll-width offcut, and the length allowance for trimming, which is why carpet orders are often larger than floor area. The diagram shows runs and seams to scale.
Formula and assumptions
- L
- room length in the roll direction
- W
- room width across the roll
Assumptions and limits
- One rectangular room laid in one direction. Not an optimized cutting plan.
- Offcuts are not reused between runs.
Worked example
A 14 × 12 ft room, a 12 ft roll, and 10% length allowance.
- 12 ÷ 12 = 1 run, no seam.
- 14 × 1 × 1.10 = 15.4 ft, rounded up to 16 ft.
- 16 × 12 = 192 sq ft = 21.3 sq yd.
These are the calculator’s default values, so the live result above matches this example until you change an input.
How to measure correctly
- Measure into doorways to the point where the carpet will meet the next floor.
- Decide the roll direction first; pile and light direction affect how seams look.
- Measure stairs separately; they are a different calculation.
Square feet to square yards
| Area | Square yards | Square meters |
|---|---|---|
| 100 sq ft | 11.1 sq yd | 9.3 sq m |
| 150 sq ft | 16.7 sq yd | 13.9 sq m |
| 200 sq ft | 22.2 sq yd | 18.6 sq m |
| 250 sq ft | 27.8 sq yd | 23.2 sq m |
| 300 sq ft | 33.3 sq yd | 27.9 sq m |
| 400 sq ft | 44.4 sq yd | 37.2 sq m |
Carpet Calculator FAQ
How do I convert square feet to square yards for carpet?
Divide by 9. A 168 sq ft room is 18.7 sq yd of floor, but the carpet order is usually more because of roll width and trimming.
What width does carpet come in?
Roll widths vary by product. The calculator starts with 12 ft as a planning example; ask your supplier for the actual width and enter it.
Why is the carpet order bigger than my room?
You buy full-width strips. A 13 ft wide room on a 12 ft roll needs two runs, leaving an 11 ft wide offcut along the second run.
Where will the seams be?
Seams fall where one run meets the next. Installers try to keep them out of high-traffic paths and away from facing windows; the diagram shows where they fall in this simple plan.
Does this include padding?
No. Pad is usually priced by floor area; use the room square footage for it.
Should I calculate rooms together?
Calculate each room separately, then add. An installer may nest pieces across rooms to save material, which this estimate does not assume.