Carpet Calculator
A carpet calculator divides room area in square feet by 9 to get square yards. A 15 × 12 ft room is 180 sq ft, or 20 sq yd; with 10% extra, order 22 sq yd.
How many square yards of carpet do I need?
Installed carpet, with pad and labor, usually costs roughly $2.50 to $8 per square foot, and premium carpet runs higher. The calculator below prices the carpet alone, in square yards.
A carpet calculator finds the floor area in square feet and divides it by 9, because one square yard is a 3 × 3 ft square. A 15 × 12 ft room is 180 sq ft, which is 20 sq yd. Tick the 10% box and the order becomes 22 sq yd. Multiply by the price per square yard to get the material cost.
Carpet stores often quote in square yards and room plans are drawn in feet, so this conversion is the first step in any carpet budget. It also gives the area for pad, which is usually sold by the same unit.
The formula, step by step
- Area = room length × room width, in feet.
- Square yards = area ÷ 9.
- With waste = square yards × 1.10, if the waste box is ticked.
- Cost = square yards × price per square yard.
The calculator does not round up, because carpet is cut to length rather than sold in fixed pieces. The installer’s cut sheet decides the final purchase.
Worked examples
- Living room: 15 × 12 ft at $25 per sq yd (calculator default)
- Area: 15 × 12 = 180 sq ft
- Square yards: 180 ÷ 9 = 20.00 sq yd
- Cost: 20 × $25 = $500.00
- With 10% waste: 22.00 sq yd, $550.00
- Bedroom: 11 × 14 ft, and why the roll width matters
- Area: 11 × 14 = 154 sq ft
- Square yards: 154 ÷ 9 = 17.11 sq yd
- With 10% waste: 18.82 sq yd, or $470.56 at $25
Here is how it gets cut. The roll is 12 ft wide, so the installer cuts one piece 12 ft wide and about 14.5 ft long, allowing a few inches at each end for trimming. That is 12 × 14.5 = 174 sq ft, or 19.33 sq yd. The extra foot of width is trimmed off and thrown away. Even the 10% buffer falls a little short here.
Square yards for common room sizes
| Room | Floor area | Square yards | With 10% |
|---|---|---|---|
| 10 × 10 ft | 100 sq ft | 11.11 | 12.22 |
| 12 × 12 ft | 144 sq ft | 16.00 | 17.60 |
| 15 × 12 ft | 180 sq ft | 20.00 | 22.00 |
| 24 × 12 ft | 288 sq ft | 32.00 | 35.20 |
| 14 × 16 ft | 224 sq ft | 24.89 | 27.38 |
| 20 × 15 ft | 300 sq ft | 33.33 | 36.67 |
Rooms 12 ft wide or less can often be done in one piece with no seam. The 14 × 16 and 20 × 15 rooms need a seam. They also need a fill strip cut from another length of roll, and that strip is where the extra waste comes from.
How to measure a room for carpet
- Measure wall to wall at the widest points, and go into door openings to the middle of the threshold.
- Add closets as separate rectangles, measured to the back wall.
- L-shaped rooms: split into two rectangles and add the areas.
- Stairs: each step takes roughly the tread depth plus the riser height times the stair width. Add them as their own line, since installers cut stairs from separate pieces.
- Note the direction of the pile. All pieces in a room should run the same way, which limits how offcuts can be reused.
Common mistakes
- Paying for floor area only. The roll-width effect in example 2 means the final bill can be higher than the square yards suggest.
- Mixing price units. A $3 per sq ft price is $27 per sq yd. Convert before comparing quotes, using the square feet to square yards calculator if needed.
- Forgetting pad and tack strip. Pad covers the same square yards. Tack strip runs around the room perimeter.
- Ignoring pattern repeat. Patterned carpet has to line up at seams, which can add a full pattern repeat per seam.
Other flooring options
If you are still choosing a floor, the flooring calculator converts the same room into boxes of laminate or vinyl plank. For basements and offices, carpet tiles avoid roll-width waste because they are laid in 2 × 2 ft squares.
Frequently asked questions
Why is carpet measured in square yards instead of square feet?
Broadloom carpet has long been priced by the square yard in the US, and many stores still quote it that way. One square yard is 3 ft × 3 ft, or 9 sq ft. A $2.78 per sq ft price is the same as $25 per sq yd, so convert before comparing quotes.
Is the square-yard total the same as what I'll actually order?
Not always. Carpet comes off a roll, commonly 12 ft wide, and the installer buys whole widths. An 11 × 14 ft room is 17.11 sq yd of floor, but a 12 ft wide piece cut 14.5 ft long is 19.33 sq yd. Ask for the installer's cut sheet before you pay.
How much waste should I add for carpet?
10% suits a simple rectangular room no wider than the roll. Rooms wider than 12 ft need a seam and a fill strip, and patterned carpet must line up across seams, so either can push waste to 15 to 20%. Stairs and closets add more.
Does this include carpet padding?
No. Pad is sold separately, usually also by the square yard, and covers the same area. Use the square-yard result for both, then add the pad price per square yard. Pad does not need pattern matching, so it wastes less than the carpet.
What's a typical price per square yard for carpet?
The $25 per sq yd default is only a placeholder. Prices vary widely by fiber, weight, and style, and installation and pad are often quoted separately. Enter the price from your own quote; 20 sq yd at $25 is $500, and at $40 it is $800.
How much does carpet cost per square foot installed?
Most cost guides put installed carpet, with pad and labor, at roughly $2.50 to $8 per square foot, with premium wool and patterned carpet above that. Labor alone is often about $1 to $4.50 per square foot, and removal and stair work are often billed separately. Get itemized local quotes before you compare prices.
Estimates only. Verify quantities with your supplier before purchasing.