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CalcBelt

Carpet calculator

Enter a room's length and width to get the carpet to buy in square yards, cut from the roll the way installers lay it out, plus the pad and a typical installed cost.

Units
Room

Wall to wall at the longest point. Where to measure

Home Depot's carpet rolls are 12 ft wide; check the one you pick.

For an L-shaped room or several rooms, run each rectangle separately and add the results.

Carpet to buy

19.3 sq yd

174 sq ft: 1 strip 14 ft 6 in long from a 12 ft roll

Floor area
154 sq ft17.1 sq yd
Pad
17.1 sq ydCovers the floor inside the tack strip
Seams
0One piece
Waste
13%Trim at the ends and sides

Cost estimate

per sq ft of floor

Floor: $770 for 154 sq ft (range $209 to $2,091)

Typical US price $1.36 to $13.58 per sq ft (HomeGuide, Fixr, October 2026). Carpet, pad and labor. Removing old carpet is extra.

Steps to carpet, priced per step.

How it's calculated
  1. Strips run along the longer side, 14 ft, across 11 ft
  2. 11 ft ÷ 12 ft roll = 0.92, rounded up to 1 strip
  3. Each strip: 14 ft + 3 in trim at each end = 14 ft 6 in
  4. 1 × 12 ft × 14 ft 6 in = 174 sq ft = 19.33 sq yd

Estimates use manufacturer data sheets and industry guides (sources). Check local codes and your supplier's figures before you order.

How to use the carpet calculator

  1. Measure the room's length and width, wall to wall, at the longest and widest points.
  2. Check the roll width of the carpet you pick; Home Depot's is 12 ft.
  3. Read the square yards to buy, the number of strips and seams, and the pad.
  4. Add stairs if you have them, and check the installed price.

How to calculate carpet

Strips = room width ÷ roll width, rounded up
Strip length = room length + 3 in at each end
Carpet = strips × roll width × strip length
Square yards = square feet ÷ 9

Example: an 11 × 14 ft bedroom with a 12 ft roll.

  • Strips run along the 14 ft side: 11 ÷ 12 = 0.92, so 1 strip
  • Strip length: 14 ft + 3 in + 3 in = 14 ft 6 in
  • Carpet: 1 × 12 × 14.5 = 174 sq ft = 19.3 sq yd
  • Pad: the floor, 11 × 14 = 154 sq ft (17.1 sq yd)
  • Installed at a typical $5 per sq ft of floor: about $770
Carpet calculator diagram: a room seen from above with its length and width measured wall to wall, carpet strips 12 feet wide running along the length with a seam between them, and 3 inches of extra carpet at each cut end for trimming.
Where to measure: the room's length and width, wall to wall. Strips run along the length, each a full roll wide, with 3 in to trim at both ends.

Why carpet comes out bigger than the floor

Carpet is cut from a roll, so the width comes in whole strips. The Carpet and Rug Institute’s standard asks for seams to run the length of the room and for every piece to lie with its pile the same way, so a narrow fill piece can’t be turned sideways to save carpet: the last strip is a full roll wide even if the room only needs part of it. Its standard also allows at least 3 in at each wall for trimming. That’s why a 14 × 20 ft room needs 492 sq ft of carpet for 280 sq ft of floor.

Rooms as wide as the roll

When a room is within 6 in of the roll’s width (11 ft 6 in to 12 ft for a 12 ft roll), the calculator still counts one strip but shows a caution. Walls are rarely square, so the installer may need a seam to reach the far wall. Check with them before you order.

L-shaped rooms and several rooms

Split an L-shaped room into two rectangles and run each one, then add the results. Do the same for several rooms. For hard floors in the same project, use the flooring calculator.

Questions and answers

How much carpet do I need?

Enough strips of the roll to cover the room's width, each cut 6 in longer than the room. An 11 × 14 ft bedroom takes one strip of a 12 ft roll, 14 ft 6 in long: 174 sq ft, or 19.3 sq yd, for 154 sq ft of floor.

How do you measure a room for carpet?

Measure wall to wall at the longest and widest points, in feet and inches. The Carpet and Rug Institute's installation standard allows at least 3 in at each wall for trimming, so the calculator adds 3 in at both ends of every strip. Carpet is priced by the square yard: square feet ÷ 9.

Why do I need more carpet than my room's square footage?

Because carpet comes off a roll in a fixed width. Every strip is a full roll wide, since all the pieces must lie with the pile in the same direction (CRI 105), and each strip is cut a little long for trimming. A 14 × 20 ft room needs two 12 ft strips: 492 sq ft of carpet for 280 sq ft of floor.

How many square yards of carpet for a 12 × 12 room?

16.7 sq yd: one strip of a 12 ft roll, 12 ft 6 in long. Because the room is as wide as the roll, check with your installer before ordering: walls are rarely square, and they may need a seam.

How much does carpet installation cost?

$2 to $8 per square foot installed, according to HomeGuide, with the carpet $1 to $5 and labor $0.50 to $1.50 of that. Fixr gives $1.36 to $13.58 and a national average of $7.47. A 12 × 12 ft bedroom (144 sq ft) runs about $290 to $1,150 at HomeGuide's range.

How much does it cost to carpet stairs?

$12 to $45 per step for carpet, pad and labor, according to HomeGuide, or $150 to $600 for a staircase with its landing. That's one cost guide's range, so get a quote.

Do I need carpet pad?

Usually, yes: Fixr notes that most manufacturers won't honor the warranty without proper padding. Pad is trimmed to the inside of the tack strip (CRI 105), so you need the room's floor area, not the carpet's.

What width does carpet come in?

Home Depot's carpet is 12 ft wide, sold cut to length or in full rolls of 12 × 90 ft (1,080 sq ft). If the carpet you pick comes in another width, enter it and the calculator works out the strips.

Sources

Figures checked October 2026.