Carpet Calculator
Carpet square feet, square yards, and cost with waste.
What it does
Carpet buying starts from room area plus a waste share for cuts, seams, and pattern matching. US stores price by the square yard (nine square feet), so the math converts before costing.
The tool above takes room length with width in feet or meters, waste percent, and unit price. It returns area with waste, square yards, and the material cost.
The default 12 by 15 ft room with 10% waste needs 198 ft² (22 yd²) for $550.00 at $25 a yard. The metric mirror of 3.66 by 4.57 m needs 18.4 m² for about $551.96 at $30 per meter.
Measuring follows CRI installation standards with World Floor Covering Association guidance behind waste allowances. Both stress measuring each rectangle separately with 5 to 10% extra for trimming.
How to use
- Pick imperial or metric for the tape.
- Enter room length and width.
- Add waste percent for cuts and seams.
- Enter price per yd² (or per m² metric).
- Read area first, then yards and cost.
Formula
- waste
- Cut share for seams and pattern.
- /9
- Square feet per square yard.
- price
- Per yd² imperial, per m² metric.
Odd rooms split into rectangles first, then add areas before waste. Stairs and halls measure as treads plus risers, not floor plan alone.
Worked example
Example: 12 by 15 ft, 10% waste, $25/yd²
Imperial defaults: 12 ft, 15 ft, waste 10, price 25.
- Net: 12 x 15 = 180 ft².
- Material: 180 x 1.10 = 198 ft².
- Yards: 198 / 9 = 22 yd².
- Cost: 22 x 25 = $550.00.
- Tool shows 198 ft², 22 yd², $550.00.
Reference table
| Waste | Material | Yards |
|---|---|---|
| 0% | 180 ft² | 20 yd² |
| 10% | 198 ft² | 22 yd² |
| 15% | 207 ft² | 23 yd² |
| 20% | 216 ft² | 24 yd² |
Limits
- Rectangles only; angles split first.
- Pad, tack, and install priced separately.
- Pattern repeats need extra beyond waste.
- Stairs need tread by tread math.
Common mistakes
- Pricing square feet at yard prices.
- Skipping waste on seam heavy rooms.
- Measuring walls instead of finished edges.
- Forgetting closets and alcoves.
- Ordering exact area with zero spare.
Try it yourself
Quick checks. Answers sit tucked under each question.
10 by 12 ft, 10% waste?
120 x 1.10 = 132 ft² = 14.7 yd².
22 yd² at $25?
22 x 25 = $550.00.
Metric 3.66 by 4.57, 10%?
16.73 x 1.10 = 18.4 m².
Questions
How much carpet for 12x15?
180 ft² net, 198 ft² (22 yd²) with 10% waste.
Square feet or yards?
Measure feet, buy yards: divide by 9 for US pricing.
How much waste?
10% plain rooms, more with angles, stairs, and patterns.
Does price include pad?
No. Pad, tack strips, and install bill separately.
Which way do seams run?
Down the long wall into low light, per install standards.
Stairs too?
Measure treads plus risers each; noses need extra.