Carpet Calculator - Roll Cuts, Seams, Pad & Cost

How to use it

1. Measure each room at its longest and widest points, into the door casings, and add the closet run. Carpet is stretched wall to wall, so the widest point is the number that matters.
2. Enter each room as a row. Name it, give the length and width in feet and inches, and switch off any room you are only pricing as an option.
3. Add the closet depth and width where the carpet runs on into a closet. The tool simply runs that cut longer, which is what an installer does.
4. Pick your roll width. 12 ft is the American standard, 15 ft is ordered in for wide rooms, and 13 ft 2 in is the 4 metre width on imported and commercial goods.
5. Enter the pattern repeat if the carpet has one. Zero means plain, and a repeat adds one whole repeat to every cut after the first.
6. Switch on stairs and set the step count, the stair width and the tread and riser depth. Choose waterfall or cap and band.
7. Turn on pad, set the doorway count so tack strip is not run across a threshold, and check the seam tape figure.
8. Edit the price lines to your own supplier and turn on removal, furniture moving or labor to build the total you want.
9. Read the order at the top, then the cut list, then the cutting plan diagram to see exactly where the seams land.
10. Holding a quote? Type the yardage and the total into the quote check at the bottom and see how they compare to the roll-cut answer.

At a glance

• 14 by 16 bedroom, 12 ft roll: 21 linear ft, 252 sq ft, 28 sq yd. Room area alone says 224 sq ft, so the roll costs 28 sq ft more.
• The same bedroom on a 15 ft roll: 16.25 linear ft, 243.75 sq ft, 27.1 sq yd, and no seam at all. Wider roll, smaller order.
• 13 steps, 3 ft 6 in wide, waterfall: 19.5 ft of runner. Three runners fit across a 12 ft roll, so the flight takes 7.75 linear ft cut in 3 pieces seamed at a riser.
• 12 by 12 bedroom, 12 ft roll: 12.25 linear ft, 147 sq ft, 16.3 sq yd. Only 3 sq ft over the room, because the room is exactly one roll wide.
• Whole house, 4 rooms plus stairs: 82.5 linear ft, 990 sq ft, 110 sq yd against 782 sq ft of floor, and about $4,366 with pad, labor, removal and furniture moving.

How the math works

Every figure comes off the roll, not off the floor. The cut length is the room run plus a 3 inch trim allowance. The number of full-width cuts is the room's across dimension divided by the roll width, rounded down, and never less than one. Whatever width is left over is the fill strip, and the number of fill strips that fit side by side across the roll is the roll width divided by the fill width, rounded down. The fill is cut in as few pieces as that allows without any piece dropping under 6 ft, because a cross seam every couple of steps shows and wears. Total linear feet is the full-width cuts plus the fill purchase plus the stairs, with the waste allowance applied to the fill and one pattern repeat added to every cut after the first, then rounded up to the quarter foot. Order area is linear feet times roll width. Square yards are square feet divided by 9, because carpet retailers still write tickets by the yard.

1. Measure to the widest point, not the average

   Carpet is stretched wall to wall and trimmed at the tack strip, so the number that decides the cut is the longest and widest point of the room, measured into the door casings and any bay. A room that is 13 ft 10 in at one end and 14 ft 1 in at the other is a 14 ft 1 in room. Add the closet as a separate depth and width: the carpet runs on into it as part of the same cut, so a 2 ft deep closet simply makes that cut 2 ft longer.

2. Decide which way the cuts run

   Every cut off one roll has to run the same direction, because carpet pile lies one way and two pieces laid against each other read as two different colours under the same light. So the first real decision is which room dimension the cuts run down. The tool lays the room out both ways and keeps the one that takes less roll, except that a saving under half a foot never justifies a longer seam. In a 16 by 24 great room, running the 24 ft way saves two inches of roll and doubles the seam, so the tool keeps the two clean 16 ft widths.

3. Take the full-width cuts first

   Full widths are the cheap part of any carpet order, because none of the roll is wasted across its width. Full cuts equal the room's across dimension divided by the roll width, rounded down, with a minimum of one. A 20 ft wide room off a 12 ft roll takes one full width and leaves 8 ft to fill. A 24 ft wide room takes two full widths and leaves nothing, which is why 24 by anything is the friendliest room on a 12 ft roll.

4. Fill the rest with strips cut the same direction

   The strip that fills the leftover width has to run the same way as the field, so it is cut from the roll along the roll length, not turned sideways. That means several fill strips come off one length of roll, side by side: a 4 ft fill takes three strips across a 12 ft roll, so 6 ft 3 in of roll yields three 4 ft by 6 ft pieces. The tool cuts the fill in as few pieces as the roll allows without dropping under 6 ft each, which is the balance the trade strikes between roll bought and seams lived with. Ask for one continuous fill instead and the tool prices that too: on a 14 by 16 bedroom it goes from 21 linear ft to 29.

5. Add the allowance and the repeat, then round to the quarter foot

   The waste allowance lands on the fill, which is the cut that gets trimmed twice and matched to the field, not on a full width that was measured. Five percent covers plain carpet and ten covers a pattern. On top of that, a patterned carpet needs one whole pattern repeat added to every cut after the first so the design lines up across each seam: five cuts of an 18 in repeat is 6 extra linear feet before anyone touches a knife. The total then rounds up to the quarter foot, which is how a roll is cut and how a retailer writes the ticket.

6. Cut the stairs across the roll

   A step takes the tread plus the riser plus a little to wrap the nosing, about 18 inches on a standard stair, so 13 steps need 19 ft 6 in of runner at the stair width. That runner does not have to be one piece. Three runners 3 ft 6 in wide fit side by side across a 12 ft roll, so the flight can be cut in three pieces of five, four and four steps and seamed at a riser where the crease hides the join, which takes 7.75 linear ft instead of 19.75. That single choice is the difference between 93 and 237 square feet of carpet on the same staircase.

7. Count what goes under and around it

   Pad is sized on the floor area, not the order, and comes off its own 6 ft roll at about 270 sq ft a roll. Tack strip runs the perimeter of every carpeted room less the doorway widths, in 4 ft sticks, plus two strips per stair step. Seam tape is the total seam length plus five percent. None of these are big money on their own, and all of them are the reason a job that was quoted for carpet alone comes back with a second invoice.

Worked scenarios, start to finish

Real jobs with the numbers carried all the way through, so you can see how the estimate is built and check your own figures against them.

The judgement calls a pro makes

Decisions the tool cannot make for you, and how someone who does this for a living thinks them through.

Where to put the seam

A seam is a permanent decision. Put it out of the main walking line, away from the doorway where everyone pivots, and running away from the strongest window rather than across it, because raking light across a seam is what makes it visible. In a bedroom the ideal seam runs under where the bed will sit. The tool picks the layout with the shortest seam, but it cannot see your windows or your furniture, so look at the cutting plan diagram and ask your installer to shift the seam if it lands somewhere you will walk every day.

When a 15 ft roll beats a 12 ft roll

Purely when the room's shorter dimension falls between 12 and 15 feet. A 13 by 18 room off a 12 ft roll needs a 1 ft fill strip down its whole length, which is a seam a foot from the wall for no good reason. On a 15 ft roll it is one clean cut. Where the room fits inside 12 ft, a 15 ft roll only sells you 3 ft of width you will throw away, and where the room is over 15 ft you are seaming either way. Run the roll width comparison table on your own numbers before you commit to the goods, because the answer flips on a foot.

Whether to cut the stairs from the same roll

Almost always yes. A staircase needs a strip about 3 ft 6 in wide, and every room job leaves offcuts of roughly that width when the room is narrower than the roll. Cutting the stairs from the same roll keeps the dye lot identical between the landing and the flight, which matters more on stairs than anywhere else in a house because you see both surfaces at once. Ordering the stairs separately, later, is how people end up with a landing that does not match the flight.

Pieced fill against one continuous fill

A pieced fill is standard, cheaper and invisible when it is done well. It puts cross seams in the strip along the edge of the room, which is where the furniture sits. A continuous fill has one long seam and nothing else, and on a 14 by 16 bedroom it costs eight extra linear feet, about $100 of carpet at planning prices. Choose the continuous fill for a loop pile or a berber, where cross seams are hardest to hide, and for a room with a hard floor line of sight down the fill.

Pad quality against carpet quality

If the budget is fixed, the pad is the better place to spend the last hundred dollars. Pad carries the crush, so a cheap 3 lb pad under a good carpet will let the carpet mat years early, while an 8 lb rebond under a mid carpet keeps it looking new. The usual residential answer is 8 lb rebond at 7/16 in thickness, and most carpet warranties require at least that. Thicker is not automatically better: over 1/2 in the carpet flexes at the backing and the seams work loose.

Which way the cuts run when the tool can go either way

When both orientations take about the same roll, the tool keeps the shorter seam. Sometimes you should override that. In a hallway the cheapest layout runs cuts across the hall, which puts the pile and every seam at right angles to the way people walk. It is the least roll and the worst wear. Down a hall you actually use every day, run the cuts the length of the hall and accept the extra roll, and tell the installer that is a decision, not an error.

Common mistakes, and the fix

• × Buying by room area: multiplying length by width and ordering that many square feet.

  ✓ Order by the roll. A 14 by 16 room is 224 sq ft of floor and 252 sq ft of carpet, and the 28 sq ft gap is not optional. Every calculator that stops at length times width will leave you a fill strip short.

• × Ignoring the pattern repeat and assuming a patterned carpet costs the same to fit as a plain one.

  ✓ Add one whole repeat to every cut after the first. On a large repeat the pattern allowance alone can cost most of an extra cut, which is why the trade quotes patterned goods at a 10 percent allowance rather than 5.

• × Letting a fill strip be turned sideways so it fits a shorter offcut.

  ✓ Never rotate a piece against the pile. Carpet laid at 90 degrees to its neighbour reads as a different colour under the same light, and no amount of stretching or seaming fixes it. If the fill will not run the same way, buy the roll length.

• × Forgetting the closet run and the nosing wrap on the stairs.

  ✓ Enter the closet depth so the cut simply runs longer, and set the per-step allowance so each step carries tread plus riser plus the wrap. Those two omissions are the classic reason a job comes up a few feet short on the last day.

• × Assuming an installer's yardage is padded because it is bigger than the room.

  ✓ Check it against the roll-cut answer first. Most of the gap is roll width you cannot use. Type the quoted yardage into the quote check and you will see in one line whether it is roll math or padding, and what to ask about if it is neither.

• × Reusing the old pad to save money on a re-carpet.

  ✓ Replace it. Pad compresses permanently under traffic and holds every spill the old carpet let through, and most carpet warranties are void over used cushion. It is the cheapest line on the ledger and the one that decides how the new carpet ages.

• × Measuring to the door rather than into the doorway.

  ✓ Measure into the door casing on every opening. Carpet finishes under the closed door, not at the room side of the threshold, and a few inches on four doorways is the difference between a clean trim and a visible gap.

Material and unit specifics

Broadloom and roll width

Broadloom is carpet woven on a wide loom and sold off a continuous roll. In the US that roll is 12 ft wide on almost everything a showroom stocks, with 15 ft ordered in for wide rooms and 13 ft 2 in (4 metres) on imported and commercial goods. The roll width is fixed by the loom, which is why it cannot flex to suit your room and why every order carries width you will not lay.

Square yards, and why retailers still use them

Carpet has been priced by the square yard since it was woven by the yard, and plenty of stores still write tickets that way while quoting a per-square-foot price in the ad. One square yard is 9 square feet, so a $22.50 per sq yd carpet is $2.50 per sq ft. The tool shows both everywhere so a quote in either unit can be checked without arithmetic.

Fiber, and what each one actually costs

Olefin runs about $1.00 to $2.00 per sq ft, is bleach-safe and fade-proof, and crushes permanently under traffic. Polyester is $1.50 to $3.00, soft and naturally stain-resistant, and mats in a hallway sooner than nylon. Nylon is $2.50 to $5.00 and is the durability standard, springing back from crushing and taking stain treatment well. Wool is $5.00 to $12.00 and is the best of all of them to live with, at several times the price and with no tolerance for bleach.

Face weight and pile

Face weight is the ounces of yarn per square yard of carpet, so 40 oz nylon has more yarn in it than 30 oz nylon of the same construction. It is a useful comparison within one fiber and one construction, and meaningless across them. Cut pile shows footprints and vacuum lines, loop pile like berber does not but snags, and cut and loop patterns hide traffic best. Pile direction is the reason every cut off one roll must run the same way.

Pad, cushion or underlay

Rebond is the speckled recycled foam under most residential carpet, rated by pound density: 6 lb is the budget grade, 8 lb at 7/16 in thickness is the residential standard and what most warranties require. Memory foam and rubber pads cost more and feel softer underfoot but can be too soft for a loop pile. Pad comes on a 6 ft roll, about 270 sq ft a roll, and is priced per sq ft or per sq yd separately from the carpet at $0.25 to $1.00 per sq ft.

Tack strip and seam tape

Tack strip is the thin wood batten with angled pins that grips the carpet backing around the room perimeter, sold in 4 ft sticks and nailed about a pile-thickness away from the wall. It runs everywhere except across doorways, where a transition takes over, and stairs eat it: two strips per step, one at the back of the tread and one at the base of the riser. Seam tape is a heat-activated adhesive tape ironed under a seam, sized to the total seam length plus a little spare.

The 18 inches per step figure

A standard step is a 10 in tread and a 7.5 in riser, and the carpet has to wrap the nosing, so about 18 in of carpet covers one step in a waterfall install. Cap and band, where the tread is upholstered and the riser banded separately, adds roughly an inch a step for the extra wrap and tuck. Both are editable here because a stair with a deep tread or a thick nosing genuinely needs more, and a straight-run basement flight with a 9 in tread needs less.

Carpet weight and getting it home

Broadloom with its backing runs about half a pound per square foot, so a 14 ft cut off a 12 ft roll is around 85 lb and a 20 ft cut is over 120. That is a two-person lift and an object as long as the roll is wide, which is why carpet is delivered rather than collected and why the cut list matters before the delivery is booked.

Reading your result

Read the two numbers at the top together, because the contrast is the whole point. The left figure is your floor measured the ordinary way, length times width. The right figure is what actually comes off the roll, and the gap between them is the fill strip plus the roll width nobody can lay. A gap of 5 to 15 percent is a normal, well-planned order. A gap over 30 percent means the room and the roll are fighting each other, and it is worth checking whether the other roll width fixes it or whether the cuts should run the other way. Below that, the cut list is what an installer would actually cut, and the cutting plan diagram shows where every seam lands, with the pile arrows on every piece so you can see they all run one way. The cost ledger is a planning ledger, not a quote: every line is editable, every default sits mid-band, and the band printed under the total is what the same job costs at the low and high ends of normal US pricing. If your quote sits inside that band, the price is ordinary and the conversation should be about the goods.

Limitations

• This computes the standard trade layout: full-width cuts plus fill strips from one roll width, all running the same direction. It is not a free-form nesting solver, and a good installer standing in your house may find a smarter layout using offcuts from another room. Treat the cut list as the honest baseline that a quote should be measured against.
• The tool cannot see your windows, your doorways or where the bed goes, and those are what really decide where a seam should land. Use the cutting plan to start the conversation, not to end it.
• Prices are editable planning defaults with honest ranges printed beside them, gathered from typical US retail. They are not quotes, they are not regional, and carpet pricing moves with the goods, the store and the week.
• Stairs are figured as a straight flight with uniform steps. Winders, pie-shaped treads, open sides with spindles and bullnose bottom steps all need extra carpet and extra labor that no calculator can size sight unseen. For the geometry of the staircase itself, use the stair calculator.
• Loop pile and berber show seams more than cut pile does, so a plan with an acceptable seam count in plush may still be one seam too many in a loop. Where seams matter, price the wider roll and the continuous fill option and compare.
• Carpet as a category is losing floor share to hard surfaces, and older cost guides on the web reflect prices from a market that has changed. Check the printed ranges against a current local quote rather than trusting any published figure, including these.
• This page covers broadloom carpet, its pad and its tack strip. For plank, laminate, vinyl or hardwood sold by the box, use the flooring calculator instead, and for carpet tiles use the flooring calculator's area mode.

Frequently asked questions

How much carpet do I need for a 12 by 12 room?

About 12.25 linear feet off a 12 ft roll, which is 147 square feet or 16.3 square yards. Not 144 square feet. The room happens to be exactly one roll wide, so it takes a single full-width cut with no fill strip and no seam, and the only extra is the 3 inch trim allowance on the cut. A 12 by 12 room is the friendliest carpet job there is, and it is the reason so many bedrooms are built at that size.

Why is my carpet order bigger than my room's square footage?

Because carpet is cut off a fixed-width roll and your room is not roll-shaped. Two things create the gap. First, any room narrower than the roll still buys the full roll width down its whole length, so a 10 ft wide room off a 12 ft roll pays for a 2 ft strip it cannot lay. Second, any room wider than the roll needs a fill strip seamed in, and that strip is bought off the roll length as well. A normal order is 5 to 15 percent over the floor area. On a 14 by 16 bedroom that is 252 square feet of carpet for 224 square feet of floor.

How much does carpet installation cost?

In the US, roughly $3 to $8 per square foot installed for carpet, pad and labor together, with wool and stairs pushing above it and builder-grade olefin sitting below. Split out, that is carpet at $1 to $5 per sq ft, pad at $0.25 to $1.00, install labor at $0.50 to $1.50 per sq ft, stairs at $8 to $15 a step and old carpet removal at $0.50 to $1.00 per sq ft. Furniture moving is usually a flat fee. The ledger on this page is built from exactly those lines with mid-band defaults you can edit, and it prints the low-to-high band under the total so you can see whether a quote is ordinary.

How do I measure stairs for carpet?

Count the steps, measure the stair width wall to wall at the tread, and measure one tread depth and one riser height. Allow tread plus riser plus a little to wrap the nosing, about 18 inches a step on a standard stair. Thirteen steps is then 19 ft 6 in of runner at the stair width. Whether that costs you 19.75 linear feet or 7.75 depends on whether the flight is one unbroken runner or cut across the roll and seamed at a riser, and this tool prices both.

How do I check my installer's quote?

Take the yardage off the quote and compare it to the roll-cut answer for the same rooms. Type both into the quote check at the bottom of this page and it will tell you the difference as a percentage. Within about 12 percent, the quote is roll math and the number is fine. Well above that, ask which way the cuts run, where the seams land and whether attic stock is included, because a one-piece run or a pattern repeat legitimately explains a big gap and so does padding. Below the roll-cut answer, ask to see the cut list, because a quote priced off room area will come up short of a fill strip on install day.

How much does it cost to remove old carpet?

Typically $0.50 to $1.00 per square foot including hauling it away, and some installers fold it into the labor rate rather than listing it. It covers pulling the carpet and pad, lifting the old tack strip where it is worn, and disposal, which is most of the cost because carpet is bulky and landfills charge by volume. Turn the removal line on in the ledger to see it against the rest of the job: on a 780 square foot floor it is about $470, which is often more than the pad.

Is a 15 ft roll better than a 12 ft roll?

Only when your room's shorter dimension falls between 12 and 15 feet. Then the wider roll turns a seamed room into a single clean cut, and it frequently orders fewer square feet as well: a 14 by 16 bedroom is 252 square feet with a seam on a 12 ft roll and 243.75 with none on a 15 ft roll. If your room fits inside 12 feet the wider roll just sells you width you will throw away, and if it is over 15 feet you are seaming either way. The roll width comparison on this page runs your own numbers through all three widths so you can see which way it falls.

How many square feet are in a square yard of carpet?

Nine. A square yard is 3 feet by 3 feet, so to convert a square foot figure to square yards divide by 9, and to go back multiply by 9. Prices convert the same way: carpet advertised at $2.50 per square foot is $22.50 per square yard, and a store quoting $27 per square yard is charging $3 per square foot. Every figure on this page is shown in both units because carpet is one of the last trades that still writes tickets by the yard.