Carpet Calculator — Square Yards, Padding & Cost
Estimate square yards (or m²) of carpet, padding, and total cost for any room. Accounts for roll width and seams, and supports both 12 ft and 15 ft US rolls plus metric (3.66 m / 4 m / 5 m).
Carpet Calculator
Carpet Roll Widths and Seam Planning
US carpet typically comes in 12-ft (3.66 m) or 15-ft (4.57 m) rolls. Metric carpet (UK/EU/AU) is sold in 4 m and 5 m widths. Whenever the room dimension exceeds the roll width, you need a seam.
- 12-ft (3.66 m) roll: standard width — covers most bedrooms and small living rooms seam-free.
- 15-ft (4.57 m) roll: wider option for larger rooms; reduces seams in 13–15 ft rooms.
- 4 m roll (metric): standard EU/UK width.
- 5 m roll (metric): wider EU/UK option.
- Plan seams under furniture or perpendicular to the main entry — never down the middle of a high-traffic walkway.
- Pile direction (nap) must run the same way across all pieces, including padding seams.
How to Measure a Room for Carpet
- Measure the longest length and widest width in feet (or meters). Round up to the nearest 6″ (15 cm).
- Multiply length × width = area in sq ft (or m²).
- Divide by 9 to convert sq ft → sq yd. (Or by 10.764 for sq ft → m².)
- For irregular rooms, break into rectangles and measure each separately. Add areas.
- For closets and alcoves, include them — you’ll want carpet there too.
- Add 10% waste for cuts, pile direction, and seam matching. 15–20% for stairs or complex shapes.
- Order by linear feet/meters — carpet rolls are sold per running length at a fixed roll width.
Imperial example: 15×12 ft room → 180 sq ft ÷ 9 = 20 sq yd. With 10% waste: 22 sq yd. Order one 15-ft length of 12-ft roll = 20 sq yd usable, no seams.
Metric example: 4.6×3.7 m room → 17 m². With 10% waste: 18.7 m². Order one 4.6 m length of 4 m roll = 18.4 m² (one seam needed since room is 4.6 m wide).
Carpet Padding Guide
| Padding Type | Density / Thickness | Best For | Cost (per sq ft) |
|---|---|---|---|
| Rebond foam (standard) | 6 lb / 7/16″ (11 mm) | Most residential rooms | $0.30–$0.50 |
| Rebond (premium) | 8 lb / 1/2″ (12.7 mm) | Plush carpet, master bedrooms | $0.50–$0.80 |
| Memory foam | 10 lb / 1/2″ (12.7 mm) | Luxury, comfort upgrade | $0.80–$1.20 |
| Slab rubber | 22 lb / 3/8″ (9.5 mm) | Commercial, heavy traffic | $1.00–$2.00 |
| Berber-rated | 8 lb / 3/8″ (9.5 mm) | Berber and looped carpets (firmer) | $0.50–$0.80 |
| Moisture barrier | varies | Pet homes, basements | +$0.20–$0.40 |
Building codes typically cap padding density at 8 lb and thickness at 7/16″ (11 mm) to prevent excessive carpet stretch. Always check carpet warranty — using the wrong padding can void it.
Carpet Types and Cost per Square Yard
| Type | Cost (per sq yd) | Cost (per m²) | Best For |
|---|---|---|---|
| Polyester (PET) | $15–$25 | $18–$30 | Bedrooms, low traffic, budget |
| Nylon (most popular) | $20–$45 | $24–$54 | Family rooms, hallways, high traffic |
| Olefin/PP (Berber) | $15–$30 | $18–$36 | Basements, commercial, stain-resistant |
| Wool (natural) | $50–$120 | $60–$144 | Luxury, eco-conscious |
| Triexta (SmartStrand) | $30–$60 | $36–$72 | Pets, kids, high stain resistance |
Add $5–$10 per sq yd for installation labor and ~$3–$6 per sq yd for padding. Total installed cost typically runs $3–$11 per sq ft ($32–$118/m²).
Frequently Asked Questions
How many square yards of carpet for a 15×12 room?
15 × 12 = 180 sq ft ÷ 9 = 20 sq yd (16.7 m²). With 10% waste: 22 sq yd. If carpet comes in 12-ft (3.66 m) rolls, you need one 15-ft (4.6 m) length with no seams.
How do I calculate carpet in square yards?
Multiply room length × width in feet, then divide by 9. Example: 12 ft × 10 ft = 120 sq ft ÷ 9 = 13.3 sq yd. Round up to 14 sq yd. For metric, work in m²: 3.66 m × 3.05 m = 11.16 m².
Do I need carpet padding?
Yes. Padding is recommended for virtually all carpet installations. It extends carpet life by ~50%, improves comfort, dampens sound, and adds insulation (R-value 0.5–1.0). Standard 7/16″ (11 mm) padding works for most applications; 1/2″ (12.7 mm) for plush/luxury carpets.
How much does carpet installation cost?
Carpet: $2–$7 per sq ft ($18–$63 per sq yd / $22–$75/m²) for materials. Installation labor: $1–$3 per sq ft. Padding: $0.30–$0.60 per sq ft. Total installed: $3–$11 per sq ft ($32–$118/m²).
Related Calculators
- Tile Calculator — tiling instead of carpeting?
- Paint Calculator — painting the room too?
- Wallpaper Calculator — new wall coverings?
- Drywall Calculator — new drywall before flooring?
- Area Unit Converter — convert between square feet, square meters, acres, hectares
- All Construction Calculators
Square yards = sq ft ÷ 9. Square meters = sq ft × 0.0929 (or sq yd × 0.836). Carpet sold by linear length × roll width — you may need to order more linear footage than the room area suggests, since unused width on a strip is still paid for. Always allow at least 10% waste.
