How much carpet do I need for a room?

Cut the room into strips the width of the roll. The strips run along one side and the other side divided by the roll width, rounded up, is how many you need. Each strip is the run plus about 3 in at each end for trimming. A 16 × 14 ft room on a 12 ft roll needs 2 strips of 14.5 ft along the 14 ft side, 29 ft off the roll, 39 square yards. Multiplying the area by a waste percentage would give 27.4 sq yd with 10%, which is about 11 sq yd short of what you need to buy: carpet waste comes from the roll width, not from a percentage.

Why is the carpet I have to buy more than the floor area?

The roll is a fixed width. A 14 ft side on a 12 ft roll takes two strips, and the second is mostly cut away: only 2 ft of its 12 ft width is used. For the 16 × 14 ft example the floor is 24.9 sq yd and the roll bought is 39 sq yd. A room whose side is just over the roll width wastes the most. The table of square yards by roll width shows where a 13 ft 2 in or a 15 ft roll helps.

Which way should the carpet run?

Usually the way that takes the least roll and puts the seams where they show least. This calculator tries both sides and keeps the shorter. For the 16 × 14 ft room, strips along the 14 ft side take 29 ft (39 square yards); along the 16 ft side they take 33 ft (44 square yards). Installers also run seams toward the main light and away from the doorway and the traffic path, so choose the direction on the calculator if you want a side other than the cheapest.

How many seams will there be?

One fewer than the strips: 1 for the example room, none for a room no wider than the roll (a 12 × 12 ft room needs 1 strip of 12.5 ft, 18 square yards). Seam tape is the length of the seams, 14 ft for the example. The seam count is a buy estimate: a real installer may lay the seams differently, for the light, the traffic or a remnant, so have them confirm the layout before you order.

What does pile direction change?

Cut-pile and plush carpet looks lighter or darker depending on which way the pile leans, so every piece has to run the same way and a leftover strip cannot be turned. That is the default here. Loop and flat-weave carpet has no pile direction, so a narrow leftover strip can be turned crosswise when that takes less roll, at the cost of a seam that shows. A 15 × 13 ft room on a 12 ft roll takes 36 square yards with every piece the same way and 26 square yards with the leftover turned, with 2 seams instead of 1.

How much carpet do stairs need?

About 18 in of roll for a 36 in wide step (typical: the tread, the riser and the wrap at the nosing). A 12 ft roll gives four step pieces across, so 13 steps take 4 rows of 18 in, 6 ft of roll. Add the 13 steps to the 16 × 14 ft room and the total goes from 39 to 47 square yards. This is an estimate: a real staircase varies with the nosing, the width and the style of the stairs, so ask the installer.

How much pad do I need?

The room area in square yards, rounded up: 25 square yards for the 16 × 14 ft room. Pad is laid wall to wall in its own pieces, so it carries none of the carpet’s roll-width waste. Pad is sold in rolls of a set width, so a few extra square feet of cuts are normal; use the underlayment calculator if you are laying under a floating floor.

How much tack strip do I need?

Tack strip runs along the walls, so it is the room perimeter less the doorways: 2 × (16 + 14) = 60 ft less 3 ft for one doorway is 57 ft for the example room, about 15 lengths of 4 ft, a common length. Stairs have their own tack strips at the back of each tread, which are not counted here.

How much extra do I need for a patterned carpet?

A pattern has to match across the seams, so each strip may need to be cut longer, to the pattern repeat. 10% extra is a typical allowance, not a rule: the sample book gives the repeat, and the installer works out the real figure. 10% on the 16 × 14 ft room is 43 square yards instead of 39.

Which roll width should I choose?

Whichever the style is woven in, and the one that wastes least for your room. In the US that is mostly 12 ft, with 13 ft 2 in and 15 ft also made; 4 m and 5 m rolls are common elsewhere. The 16 × 14 ft room takes 39 square yards on a 12 ft roll and 29 on a 15 ft roll, which also gets rid of the seam.

Carpet Calculator: How Much Carpet Do I Need?

A 16 × 14 ft room (224 sq ft) on a 12 ft roll takes 39 square yards of carpet: 2 strips of 14.5 ft (14 ft plus 3 in trim at each end, running along the 14 ft side) and 1 seam, 29 ft off the roll. That is more than the 24.9 sq yd of floor, because the roll is 12 ft wide and the second strip is mostly cut away. Add 25 square yards of pad (the room only, with no roll-width waste) and about 57 ft of tack strip with one doorway. The seam count is a buy estimate: a real installer may lay seams differently.

Figures based on the sources listed belowUpdated 2026-10-04How we calculate

Room length

Room width

Extra carpet

Cut plan only (0%): it already has the trim allowancePatterned carpet: allow for the match (+10%, typical)Custom

Roll widthThe width the carpet is woven in; the label or the sample book says. Most US carpet is 12 ft, and 13 ft 2 in and 15 ft also exist. Metric markets use 4 m and 5 m.

Strips run alongSeams usually run toward the main light and away from the doorway, so you may want a particular side even if it takes more roll.

Pile directionCut-pile carpet changes shade with the pile direction, so every piece goes the same way. Turning the leftover strip can save roll on a narrow remainder, at the cost of a seam that shows.

Trim at each end of a strip (in)

Carpet is cut oversize and trimmed at the walls. 3 in at each end is typical; ask your installer.

Stair steps

Each step takes about 18 in of roll at 36 in wide (typical: tread, riser and the wrap at the nosing). Leave 0 for none. Landings are rooms: measure them as one.

Doorways

Tack strip is laid along the walls and left out across doorways. Each doorway takes 3 ft (a typical door) off the perimeter.

Price per square yard (optional)

Buy 39 square yards

224 sq ft + 0% waste = 224 sq ft

Strips (drops) off the roll: 2 strips (each 14.5 ft), running along the width
Seams (with hot-melt seam tape): 1 seam (tape 14 ft), a buy estimate: an installer may lay seams differently
Carpet off the roll: 29 ft (roll width 12 ft)
Pad (underlay): 25 square yards, the room area, with no roll-width waste
Tack strip (4 ft lengths): 15 lengths (≈ 57 ft), perimeter less doorways

How this number is calculated

224 sq ft (no waste added) ÷ 5.74 sq ft per square yard = 39 square yards

Shopping list

Carpet tack strip
Hot-melt carpet seaming tape
Knee kicker (carpet stretcher)
Carpet utility knife and blades
Carpet stair tool
Chalk line

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Square yards of carpet for common room sizes on a 12 ft roll

Best-fit strips, 3 in trim at each end, every piece running the same way, no extra percentage, worked by this calculator. Roll length is rounded up to a whole foot, and square yards = roll length × 12 ÷ 9, rounded up.
Room	Room area (sq ft)	Strips	Seams	Roll length (ft)	Square yards to buy
9 × 12 ft	108	1 × 9.5 ft	0	10	14
10 × 10 ft	100	1 × 10.5 ft	0	11	15
10 × 12 ft	120	1 × 10.5 ft	0	11	15
10 × 14 ft	140	1 × 14.5 ft	0	15	20
12 × 12 ft	144	1 × 12.5 ft	0	13	18
12 × 14 ft	168	1 × 14.5 ft	0	15	20
12 × 15 ft	180	1 × 15.5 ft	0	16	22
12 × 18 ft	216	1 × 18.5 ft	0	19	26
13 × 15 ft	195	2 × 13.5 ft	1	27	36
14 × 16 ft	224	2 × 14.5 ft	1	29	39
15 × 20 ft	300	2 × 15.5 ft	1	31	42
16 × 20 ft	320	2 × 16.5 ft	1	33	44

Square yards by roll width

The same rooms on 12 ft, 13 ft 2 in and 15 ft rolls, best-fit strips, 3 in trim, no extra percentage, worked by this calculator. A wider roll can drop a seam and the waste with it, but you can only buy the widths the style is woven in.
Room	12 ft roll	13 ft 2 in roll	15 ft roll
12 × 15 ft	22 (0 seams)	24 (0 seams)	22 (0 seams)
13 × 15 ft	36 (1 seam)	24 (0 seams)	24 (0 seams)
14 × 16 ft	39 (1 seam)	43 (1 seam)	29 (0 seams)
15 × 20 ft	42 (1 seam)	46 (1 seam)	35 (0 seams)
16 × 20 ft	44 (1 seam)	49 (1 seam)	55 (1 seam)

Stairs: roll length and square yards by number of steps

Each step takes an 18 in deep, 36 in wide piece (typical), so a 12 ft roll gives 4 pieces across and 1.5 ft of roll for every 4 steps. Stairs alone, no extra percentage, worked by this calculator; a real staircase may take more.
Steps	Roll for the steps (ft)	Roll length bought (ft)	Square yards
10	4.5	5	7
12	4.5	5	7
13	6	6	8
14	6	6	8
15	6	6	8
16	6	6	8

Methodology & assumptions

Carpet is sold off a roll of fixed width, so the calculator cuts the room into strips (drops) the way an installer plans it, not by area alone. The strips run along one side of the room, the run, and are laid side by side across the other side. Each strip is the run plus a trim allowance at each end (3 in is typical; carpet is cut oversize and trimmed at the walls). The number of strips is the other side divided by the roll width, rounded up: a 14 ft side on a 12 ft roll needs 2, because the second strip is mostly cut away. Seams are strips less one, each as long as the run, and seam tape is the total seam length. The roll length is strips × strip length, and square yards are that length × roll width ÷ 9, rounded up: this is what carpet is priced by in the US. By default the calculator tries the strips along each side of the room and keeps the one that takes less roll; the length side wins a tie, and you can force either. All pieces run the same way by default, which is required for cut-pile and plush carpet, whose shade changes with the pile direction. If you choose to let leftover pieces turn (loop or flat-weave carpet only), a narrow leftover strip can be covered by pieces turned crosswise when that takes less roll than another full strip: ceil(run ÷ roll width) pieces of the leftover width plus trim. That adds a seam that shows. This is a buy estimate: a real installer may lay the seams differently, to keep them out of the main light and the traffic path, away from doorways, or to use a remnant, and may ask for more or less. Always have the installer confirm the layout before you order. Stairs are counted at 18 in of roll for a 36 in wide step (typical: tread, riser and the wrap at the nosing), with floor(roll width ÷ 3 ft) steps cut across the roll width. Real stairs vary with the nosing, the width and a waterfall or a closed-string style, so treat the stair figure as an estimate. Pad (underlay) is counted as the room area in square yards: it is laid wall to wall in its own pieces, so it carries none of the roll-width waste the carpet does. Tack strip is the room perimeter less 3 ft for each doorway, and is commonly sold in 4 ft lengths. Areas you mark as having no carpet (a tile entry or a hearth) come off the room area and the pad, but not off the roll: the strips still run across the room and are trimmed round them, so if the tile takes a full strip's length off the room, enter the shorter room instead. A patterned carpet needs extra for the repeat match; 10% is a typical allowance, and the sample book or the installer gives the real figure. The metric toggle shows lengths in m and the trim in cm; carpet is still counted in square yards, as US carpet is priced.

Carpet and Rug Institute (CRI), CRI 105: Standard for Installation of Residential Carpet (seam placement, pile direction and stretch-in installation; check the current edition)
Carpet manufacturers’ product data and sample books: the roll widths a style is woven in (12 ft is the common US width; 13 ft 2 in and 15 ft also exist) and any pattern-repeat allowance
Installer practice for the trim allowance (about 3 in at each end of a strip), the stair step allowance (about 18 × 36 in a step) and tack strip in 4 ft lengths: rules of thumb, so treated as estimates on this page

How to calculate how much carpet you need

Measure the room. Measure the length and width of the room at the longest and widest points, doorways and closets included, and note the roll width the carpet is woven in.
Pick the direction of the strips. Strips run along one side of the room and are laid side by side across the other. Work out both ways and choose the one that takes less roll, unless you want the seams in a particular place.
Count the strips and the seams. Divide the side the strips stack across by the roll width and round up. The seams are one fewer than the strips. A side only a little over the roll width still needs a second strip.
Work out the roll length. Each strip is the run plus about 3 in at each end for trimming. Multiply by the number of strips and add the stairs and any extra for a pattern match.
Convert to square yards and add the supplies. Square yards = roll length × roll width ÷ 9, rounded up. Pad is the room area in square yards, tack strip is the perimeter less the doorways, and seam tape is the length of the seams.

Worked examples

Project	Result
16 × 14 ft room, 12 ft roll, 3 in trim, strips along the 14 ft side	224 sq ft → 39 square yards (2 strips of 14.5 ft, 1 seam, 29 ft off the roll)
12 × 12 ft room, 12 ft roll: one strip, no seam	144 sq ft → 18 square yards (1 strip of 12.5 ft, no seam, 13 ft off the roll)
15 × 13 ft room, 12 ft roll, every piece the same way (cut pile)	195 sq ft → 36 square yards (2 strips of 13.5 ft, 1 seam, 27 ft off the roll)
The same room in loop carpet, leftover pieces turned crosswise (estimate; the extra seam shows)	195 sq ft → 26 square yards (2 seams, 19 ft off the roll)
16 × 14 ft room on a 15 ft roll: one strip, no seam	224 sq ft → 29 square yards (1 strip of 16.5 ft, 17 ft off the roll)
The 16 × 14 ft room plus 13 stair steps (18 × 36 in a step, typical)	224 sq ft → 47 square yards (35 ft off the roll, 6 ft of it for the stairs)
5 × 4 m room on a 4 m roll: one strip, no seam	215.28 sq ft → 25 square yards (1 strip of 16.9 ft, 17 ft off the roll)

Frequently asked questions

How much carpet do I need for a room?: Cut the room into strips the width of the roll. The strips run along one side and the other side divided by the roll width, rounded up, is how many you need. Each strip is the run plus about 3 in at each end for trimming. A 16 × 14 ft room on a 12 ft roll needs 2 strips of 14.5 ft along the 14 ft side, 29 ft off the roll, 39 square yards. Multiplying the area by a waste percentage would give 27.4 sq yd with 10%, which is about 11 sq yd short of what you need to buy: carpet waste comes from the roll width, not from a percentage.
Why is the carpet I have to buy more than the floor area?: The roll is a fixed width. A 14 ft side on a 12 ft roll takes two strips, and the second is mostly cut away: only 2 ft of its 12 ft width is used. For the 16 × 14 ft example the floor is 24.9 sq yd and the roll bought is 39 sq yd. A room whose side is just over the roll width wastes the most. The table of square yards by roll width shows where a 13 ft 2 in or a 15 ft roll helps.
Which way should the carpet run?: Usually the way that takes the least roll and puts the seams where they show least. This calculator tries both sides and keeps the shorter. For the 16 × 14 ft room, strips along the 14 ft side take 29 ft (39 square yards); along the 16 ft side they take 33 ft (44 square yards). Installers also run seams toward the main light and away from the doorway and the traffic path, so choose the direction on the calculator if you want a side other than the cheapest.
How many seams will there be?: One fewer than the strips: 1 for the example room, none for a room no wider than the roll (a 12 × 12 ft room needs 1 strip of 12.5 ft, 18 square yards). Seam tape is the length of the seams, 14 ft for the example. The seam count is a buy estimate: a real installer may lay the seams differently, for the light, the traffic or a remnant, so have them confirm the layout before you order.
What does pile direction change?: Cut-pile and plush carpet looks lighter or darker depending on which way the pile leans, so every piece has to run the same way and a leftover strip cannot be turned. That is the default here. Loop and flat-weave carpet has no pile direction, so a narrow leftover strip can be turned crosswise when that takes less roll, at the cost of a seam that shows. A 15 × 13 ft room on a 12 ft roll takes 36 square yards with every piece the same way and 26 square yards with the leftover turned, with 2 seams instead of 1.
How much carpet do stairs need?: About 18 in of roll for a 36 in wide step (typical: the tread, the riser and the wrap at the nosing). A 12 ft roll gives four step pieces across, so 13 steps take 4 rows of 18 in, 6 ft of roll. Add the 13 steps to the 16 × 14 ft room and the total goes from 39 to 47 square yards. This is an estimate: a real staircase varies with the nosing, the width and the style of the stairs, so ask the installer.
How much pad do I need?: The room area in square yards, rounded up: 25 square yards for the 16 × 14 ft room. Pad is laid wall to wall in its own pieces, so it carries none of the carpet’s roll-width waste. Pad is sold in rolls of a set width, so a few extra square feet of cuts are normal; use the underlayment calculator if you are laying under a floating floor.
How much tack strip do I need?: Tack strip runs along the walls, so it is the room perimeter less the doorways: 2 × (16 + 14) = 60 ft less 3 ft for one doorway is 57 ft for the example room, about 15 lengths of 4 ft, a common length. Stairs have their own tack strips at the back of each tread, which are not counted here.
How much extra do I need for a patterned carpet?: A pattern has to match across the seams, so each strip may need to be cut longer, to the pattern repeat. 10% extra is a typical allowance, not a rule: the sample book gives the repeat, and the installer works out the real figure. 10% on the 16 × 14 ft room is 43 square yards instead of 39.
Which roll width should I choose?: Whichever the style is woven in, and the one that wastes least for your room. In the US that is mostly 12 ft, with 13 ft 2 in and 15 ft also made; 4 m and 5 m rolls are common elsewhere. The 16 × 14 ft room takes 39 square yards on a 12 ft roll and 29 on a 15 ft roll, which also gets rid of the seam.

Handy tools

Feet and Inches Calculator: Turn a tape reading such as 13' 8 1/2" into the decimal feet the room fields take.