Convert room area into carpet square yards, padding and waste for bedrooms, stairs and whole floors.
Quick answer: Carpet is sold by the square yard, and one square yard equals 9 sq ft. A 200 sq ft room is 200 ÷ 9 = 22.2 sq yd, and with 10 percent waste for seams and cuts you need about 25 sq yd of carpet, plus the same area of padding. Stairs and patterned carpet need more.
How do you want to enter the area?
sq ft
%
Cutting waste is normally 5–10%; diagonal layouts need 15%.
$
Installed carpet averages roughly $15–$40 per sq yd including pad.
Carpet to order
24.44
sq yd of carpet
Estimated material cost
$538
200 sq ft + 10% waste = 220 sq ft
Also on the shopping list
Carpet pad24.44 sq yd
Tack stripmeasure the room perimeter — strips come in 4 ft lengths
Seam tape / adhesive1 rolls for seams and stairs
Ordering one extra sq yd beats a mid-job shortage: dye lots, tile calibre and wallpaper print runs change between batches, so a later top-up may not match what you already installed.
Every coverage figure here is typical, not exact: box sizes, sheet sizes, roll widths and bag yields change between brands. Check the label on the product you actually buy and round up — a second trip costs more than a spare box.
Core facts
Square yard
9 sq ft
Typical roll width
12 ft for residential carpet
Waste allowance
5–10%, more for stairs and patterns
Padding
usually the same area as the carpet
What is Carpet Calculator?
Carpet is priced by the square yard while rooms are measured in square feet, which is where most estimates go wrong. Divide your square footage by 9 and you have the raw area. The complication is the roll. Residential carpet generally comes 12 feet wide, and a room wider than 12 feet needs two pieces with a seam, so you may pay for more carpet than the floor area suggests. Add 5 to 10 percent for cuts, doorways and closets, and budget a separate line for padding, which is bought in the same area but priced by the square yard too.
Common uses for Carpet Calculator
Convert bedroom square footage into carpet square yards
Estimate padding alongside the carpet for a whole floor
Work out extra carpet for stairs and landings
Compare the price per square yard between two products
Plan seam placement in a room wider than 12 feet
Square yards, not square feet
The most common carpet mistake is ordering by square footage. Carpet, padding and installation are all priced per square yard, and a room measured at 300 sq ft is only 33.3 sq yd. Converting early keeps every later number in the same unit and makes it easy to compare quotes from different stores on a like-for-like basis.
The 12 foot roll changes everything
Roll width is what makes carpet estimating different from tile or paint. A 14 by 16 ft room cannot be covered by one 12 ft width, so it takes two pieces and a seam, and you pay for the full length of both cuts. Measuring rooms in the direction that keeps pieces under 12 ft wide can cut the order noticeably.
Padding, seams and installation
Padding is not an optional extra. It is what gives carpet its feel and its lifespan, and it must be bought in the same area as the carpet. Seams should be placed away from traffic and direct sunlight, which sometimes means buying a little more carpet than the strict area requires. Ask the installer where the seams will fall before the order goes in.
Frequently Asked Questions
How many square feet are in a square yard of carpet?
Nine. Carpet is priced and sold by the square yard, so divide your room's square footage by 9 to get the raw quantity. Allowing for waste, a 200 sq ft room usually needs about 25 sq yd. Padding is sold the same way and normally covers the same area as the carpet.
How much waste should I add for carpet?
Five percent for a simple rectangular room with no pattern. Ten percent for rooms with closets, angled walls or several doorways. Patterned carpet with a match requirement can waste considerably more, because every strip has to align with its neighbor, so ask the installer before you order.
Do I need padding under carpet?
Yes for almost all residential installations. Padding cushions the carpet, extends its life and adds insulation and sound absorption. A pad of 6 to 8 lb density suits most homes. Thicker is not always better, because very soft pads let the carpet flex and wear at the backing, and stairs need a denser pad.
What width does carpet come in?
Most residential carpet is manufactured 12 feet wide, though 15 foot widths exist in some product lines. A room wider than the roll needs a seam, and you pay for the full width of material used even if the offcut is small. That is why measuring two adjoining rooms together can be cheaper than two separate orders.
How much extra carpet for stairs?
Allow about 1 square yard per step for an average staircase once you count the tread, the riser and the wrap over the nosing, so a typical 13 step flight needs roughly 13 sq yd. Landings and winders add more. Stairs are also where a patterned carpet's match requirement bites hardest.