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Carpet Calculator

A 15 by 12 ft bedroom runs about 19.8 square yards once you add 10% waste. Price that same yardage for a bedroom, then a stairwell, then a hallway, and you get three different numbers back. The sections below show why.

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Carpet only. Padding and installation labor price separately.

The same yardage, three different budgets

Carpet is sold by the square yard, which makes a whole-house job feel like simple math: measure every room, add up the yards, multiply by one price. That idea falls apart fast. Three rooms of identical square footage can land on three different per-yard prices, because where the carpet goes matters as much as how much of it there is.

SpaceWhat drives the price
Bedroom or living roomStraightforward roll-out, lowest labor per yard
HallwayNarrow width means more seams and trim relative to area
StairsPriced per step in many quotes, not per yard, due to wrapping each tread and riser
Formula: area (sq ft) = length x width x (1 + waste / 100). Square yards = area / 9. Cost = square yards x price per square yard.

Reading a carpet quote against this calculator

This calculator only prices the carpet itself. An installed quote piles more onto that number: padding, usually $3 to $8 per yard on top of the carpet price, labor, often $1 to $2 per square foot and billed apart from material, and stairs, which most installers price per step instead of folding into the room total. Ask your installer to break each of those out on paper, or you'll end up comparing a bare material number against someone else's all-in price.

A worked example across two rooms

Take the 15 by 12 bedroom from above: 180 square feet, 198 with 10% waste, 22 square yards. Down the hall, a smaller 10 by 9 room comes in at 90 square feet, 99 with waste, 11 square yards. Combined that's 33 square yards. At $30 a yard for material only, the bedroom runs about $660 and the second room about $330, roughly $990 total, and that's before padding or labor. Budget another $400 to $700 for those on a typical two-room job.

Padding: the line item people forget to budget

Nearly every quote treats padding as its own line item, priced by the same square yardage as the carpet. A thicker or denser pad costs more but stretches the life of the carpet on top of it, especially in a high-traffic room. Before setting two store quotes side by side, check whether padding is in either number. It's the one line item that ambushes people at checkout.

Measuring rooms that are not simple rectangles

Got a closet, a bay window, or an angled wall eating into the floor plan? Measure the main rectangle first, then each extension on its own, and add the areas together. Or run an L-shaped layout through the square footage calculator instead of doing it by hand. Push the waste number above 10% for a room shaped like this. Carpet comes off a 12 foot wide roll, so one odd cut on one side can strand material on the other side that's too small to use.

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Carpet budgeting questions

Why does carpeting stairs cost more per square foot than a bedroom?

Every stair tread and riser needs its own wrapped piece of carpet, so a twelve-step staircase means twelve small, fussy installs instead of one flat roll-out. All those extra cuts and corners add labor time fast. That's why most installers quote stairs per step instead of per square yard. Keep it out of your room total and budget it on its own.

Should a hallway use the same carpet grade as the bedrooms it connects?

Not really, no. Everyone who lives in the house walks the hallway every single day, more than they cross any one bedroom floor. A denser, higher-traffic carpet holds up longer there, even if you match the color to the bedroom next door so the transition doesn't look jarring.

How do I compare carpet quotes that price per square yard against ones that price per square foot?

Multiply a per square foot price by 9 and you've got the per square yard number. Divide a per square yard price by 9 and you've got per square foot. Do that conversion before you compare anything, because carpet retailers pick whichever unit they feel like leading with, and it's rarely the same one twice.

Does padding get added to the carpet order or priced separately?

Separately, almost every time, priced by the same square yardage as the carpet. Ask the store point blank whether padding is already folded into the number in front of you or whether it gets tacked on later. That one question is where a lot of final bills quietly jump higher than expected.

How much extra should I add for a room with a bay window or closet?

Push it to 15 to 20%, up from the standard 10% you'd use for a plain rectangle. Carpet ships in rolls that run 12 feet wide, and an oddly shaped room, one with a bay window, an angled wall, a closet cut into the corner, can leave a lot more unusable offcut lying on the floor than the square footage alone would ever tell you.