Carpet Calculator
Carpet is sold by the square yard, but you measure your room in feet — this calculator bridges the two. Enter the room length and width, add a waste percentage for seams, doorways and trimming, and you get the square yards to order, the waste-adjusted square footage, the equivalent in square metres, and the total cost when you supply a price per square yard. It runs entirely in your browser and updates instantly as you type.
How to estimate carpet
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1
Measure the room
Enter the length and width in feet. For an L-shaped room, split it into rectangles and add the largest one here.
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2
Add a waste factor
Use 10% for a simple rectangular room, more for stairs, hallways or patterned carpet that must be matched at seams.
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3
Read the order quantity
The calculator shows square yards to order, square feet including waste, square metres and the total cost if you enter a price per square yard.
The formula
Carpet is priced per square yard, and one square yard equals nine square feet. The calculation is:
- Floor area (sq ft) = length × width
- With waste = area × (1 + waste% ÷ 100)
- Square yards = area with waste ÷ 9
- Square metres = area with waste × 0.092903
- Total cost = square yards × price per square yard
Worked example — a 15 × 12 ft bedroom
- Floor area: 15 × 12 = 180 sq ft
- Add 10% waste: 180 × 1.10 = 198 sq ft
- Square yards: 198 ÷ 9 = 22 sq yd
- Square metres: 198 × 0.092903 ≈ 18.4 m²
- At $28 per sq yard: 22 × 28 = $616
Recommended waste factors
| Room type | Waste factor | Why |
|---|---|---|
| Simple rectangle | 10% | Trimming and a single seam allowance |
| Hallways / closets | 10 - 15% | Many short runs waste off-cuts |
| Stairs | 15 - 20% | Each tread and riser needs a cut piece |
| Patterned carpet | 15 - 20% | Pattern repeat must align across seams |
Common mistakes
- Buying square feet, not square yards. Showrooms quote per square yard; ordering “198” thinking in feet over-buys by nine times.
- Skipping the waste factor. Carpet comes in fixed roll widths (usually 12 ft), so a 13-ft-wide room forces a seam and extra material.
- Forgetting the nap direction. Patterned and cut-pile carpet must run the same way across seams, which can increase waste beyond the default.
- Measuring only the main rectangle. Add closets, bay windows and doorway thresholds, or you will fall short on install day.
Frequently Asked Questions
It is an industry convention — carpet rolls and pricing in many markets are quoted per square yard. One square yard equals nine square feet, so the calculator converts your foot measurements automatically.
Use about 10% for a simple rectangular room. Add 15-20% for stairs, hallways, irregular shapes or patterned carpet that must be matched at the seams. When in doubt, round up — running short means a second roll from a different dye lot.
Yes. The calculator shows square metres alongside square yards and square feet, using the conversion 1 square foot = 0.092903 square metres on the waste-adjusted area.
No. The carpet calculator runs entirely in your browser. Your room dimensions and price are never sent to a server, saved or shared.
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