Carpet Padding Calculator
Calculate how much carpet and carpet padding you need for any room or area.
Supports rectangular rooms and adds waste allowance automatically.
Installing carpet requires purchasing both the carpet itself and the pad underneath. The pad (also called underlay) provides cushioning, insulation, and extends the life of the carpet. This calculator estimates both quantities, including a standard waste allowance for cuts and seams.
The formula:
Room Area = Length × Width
Order Area = Room Area × (1 + Waste Factor)
A typical waste factor is 10% for simple rectangular rooms. For rooms with multiple angles, alcoves, or closets, use 15–20%.
Standard carpet roll widths: Carpet is sold in rolls, typically 12 feet (3.66 m) wide in North America. You will always need to round up to the next full roll width and length. Your installer will cut and seam pieces to fit the room.
Carpet padding types and thicknesses:
| Pad Type | Thickness | Best For |
|---|---|---|
| Rebond foam | 7/16 in (11 mm) | Most residential rooms |
| Rebond foam (thick) | 1/2 in (13 mm) | Heavy-traffic areas |
| Memory foam | 3/8 in (10 mm) | Bedrooms, comfort-focused |
| Rubber pad | 1/4 in (6 mm) | Berber / loop carpets |
| Flat pad | 3/16 in (5 mm) | Commercial / low pile |
Typical carpet costs (United States):
- Budget carpet: $1–3 per ft² ($10–32 per m²)
- Mid-range carpet: $3–5 per ft² ($32–54 per m²)
- High-end carpet: $5–10+ per ft² ($54–108+ per m²)
- Carpet padding: $0.50–2.00 per ft² ($5–22 per m²)
- Installation: $1–2 per ft² ($10–22 per m²)
Metric note:
- 1 square yard = 0.836 m²
- 1 square foot = 0.0929 m²
- Carpet is often sold by the square yard in older US pricing
Tips for buying carpet:
- Always measure twice before ordering.
- Buy from the same dye lot for color consistency.
- Thicker pads feel more luxurious but are not always better — check manufacturer recommendations for your carpet type.
- Berber and loop carpets require a thinner, firmer pad to avoid stretching.
- Ask your installer about the seam placement before cutting begins.