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Free online carpet calculator

Carpet is sold by the square yard, not the square foot. This calculator converts room dimensions to square yards and estimates total cost including padding and installation.

About this calculator

How to use

  1. Enter room length and width in feet.
  2. Set a waste factor — 10% is standard for rectangular rooms.
  3. Enter carpet, padding, and installation costs per square yard.
  4. Toggle padding on or off depending on your installation plan.
  5. Read total cost and a breakdown by material, padding, and labor.

Formulas

area (sq ft)   = length × width
area (sq yd)   = area (sq ft) ÷ 9
carpet needed  = area (sq yd) × (1 + waste% ÷ 100)

carpet cost    = carpet needed × carpet $/sq yd
padding cost   = carpet needed × padding $/sq yd  (if padding enabled)
install cost   = carpet needed × install $/sq yd
total cost     = carpet cost + padding cost + install cost

Worked example

Room 15 ft × 12 ft, 10% waste, $30/sq yd carpet, $5 padding, $6 installation:

area           = 15 × 12        = 180 ft²
area (sq yd)   = 180 ÷ 9        = 20 sq yd
with waste     = 20 × 1.10      = 22 sq yd

carpet cost    = 22 × $30       = $660
padding cost   = 22 × $5        = $110
install cost   = 22 × $6        = $132
total          =                  $902

Notes

  • Prices vary significantly by region and carpet type (Berber, plush, frieze, etc.). Get quotes from local installers before finalizing your budget.
  • Always buy carpet from the same dye lot — different lots can have subtle color variations.
  • Padding density (measured in pounds per cubic foot) affects durability more than thickness. Aim for 6–8 lb density for residential use.
  • Stair carpet is calculated separately and uses more material per tread-riser than flat floor estimates suggest.

Frequently asked

How do I calculate square yards of carpet?
Multiply room length by width (in feet) to get square feet, then divide by 9 to convert to square yards. Always add a waste factor of 10–15% for seams and cuts.
Why is carpet measured in square yards?
Carpet has traditionally been manufactured and sold in 12-foot wide rolls, and the industry settled on square yards as the billing unit. One square yard equals 9 square feet.
What waste factor should I use for carpet?
A 10% waste factor is standard for simple rectangular rooms. Add more for L-shaped rooms, diagonal patterns, or rooms with many obstacles. Installers typically recommend 10–15%.
Do I need padding under carpet?
Yes for most residential installations. Padding extends carpet life by absorbing foot-impact stress, and it improves comfort underfoot. Some commercial carpets are glued directly without padding.
How much does carpet installation cost per square yard?
Professional installation typically runs $3–$10 per square yard depending on region, carpet type, and whether furniture moving is included. The calculator default of $6/sq yd is a national midpoint estimate.
How do I share my carpet calculation?
Click Share to copy the page link, or Share with my numbers to include your room dimensions and pricing in the URL.

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