Carpet Calculator
Square yards of carpet for a room
Carpeting a room? Enter the dimensions to get the area in square yards (how broadloom carpet is priced), square feet, and the number of carpet tiles if you're using those instead. Work in feet or metres, and the calculator adds waste for seams and roll width.
Square feet vs. square yards
How much carpet do I need is really two questions: how many square feet the floor is, and how many square yards that becomes. This works as a carpet square footage calculator and a carpet yardage calculator at the same time, and adding a price turns it into a carpet cost calculator.
Carpet is the one flooring material still sold by the square yard in the US, and one square yard is 9 square feet. To convert, divide your square footage by 9. A 12 × 15 ft room is 180 ft², which is 20 square yards before waste.
This trips people up constantly, because everything else in the house is quoted per square foot. If a quote looks suspiciously cheap, check whether it is per square yard: the same carpet at "$30" is nine times more expensive per yard than per foot.
Quick conversion: square feet ÷ 9 = square yards. Square yards × 9 = square feet.
Carpet square yard conversion chart
Common room sizes, with and without the 10% waste allowance for seams and roll offcuts.
| Room size | Square feet | Square yards (bare) | Square yards (+10%) |
|---|---|---|---|
| 10 × 12 ft | 120 ft² | 13.3 | 14.7 |
| 12 × 12 ft | 144 ft² | 16.0 | 17.6 |
| 12 × 15 ft | 180 ft² | 20.0 | 22.0 |
| 14 × 16 ft | 224 ft² | 24.9 | 27.4 |
| 12 × 20 ft | 240 ft² | 26.7 | 29.3 |
| 15 × 20 ft | 300 ft² | 33.3 | 36.7 |
| 20 × 20 ft | 400 ft² | 44.4 | 48.9 |
How many carpet tiles do I need?
Carpet tiles are sold by the tile or by the box, not by the yard, and the count depends entirely on tile size. Divide your area by the coverage of one tile and add 10%.
| Tile size | Coverage each | Per 100 ft² | Per 10 m² |
|---|---|---|---|
| 50 × 50 cm | 0.25 m² (2.69 ft²) | 37.2 | 40 |
| 18 × 18 in | 2.25 ft² | 44.4 | 47.8 |
| 20 × 20 in | 2.78 ft² | 36.0 | 38.8 |
| 24 × 24 in | 4.00 ft² | 25.0 | 26.9 |
Carpet tiles waste far less than broadloom because offcuts from the perimeter are reusable on the opposite wall, and a damaged tile is replaced individually rather than re-carpeting the room. That is why they dominate offices and increasingly appear in basements and playrooms.
Roll width and seam planning
Broadloom carpet is made on 12-foot-wide rolls (some ranges also come in 15 ft). A room wider than the roll needs a seam, and the trimmed strip is often unusable, which is why real-world waste runs higher than the bare arithmetic suggests.
Plan seams away from doorways and main traffic paths, and run the pile in one consistent direction across the whole room. Pile direction changes how carpet reflects light, so a piece laid the wrong way looks like a different colour even when it is from the same roll.
Worked example: carpeting a 12 × 15 ft living room
| Step | Working | Result |
|---|---|---|
| Floor area | 12 × 15 | 180 ft² |
| Add 10% waste | 180 × 1.10 | 198 ft² |
| Square yards | 198 ÷ 9 | 22 sq yd |
| Roll cut needed | 12 ft wide × 15 ft long | no seam |
| If using 50 cm tiles | 198 ÷ 2.69 | 74 tiles |
Because the room is exactly 12 ft in one direction, a single roll width covers it with no seam at all. Rooms 13 or 14 ft wide are the awkward ones: they need a full second strip of which most becomes waste, so real waste can reach 25% rather than 10%.
What carpet costs
Carpet commonly runs $2 to $8 per square foot for the material, which is roughly $18 to $72 per square yard — the unit most quotes actually use. Professional installation typically adds $1 to $2 per square foot, and that usually includes removing and disposing of the old floor.
Budget separately for the cushion pad, tack strips, and transition strips at doorways. Enter a price per square yard above to get a total.
Don't forget the pad
Carpet needs a separate cushion pad underneath, ordered to the same area. A good pad (typically 6 to 8 lb density for living areas) extends carpet life considerably and changes how the floor feels far more than most people expect. Stairs and high-traffic rooms want a firmer, denser pad, not a thicker soft one.
Carpet ordering mistakes
- Confusing square feet with square yards. A factor-of-nine error is the most expensive mistake on this page.
- Ignoring roll width. A 13 ft wide room wastes far more than a 12 ft one.
- Mixing pile direction. Same carpet, laid two ways, reads as two colours.
- Forgetting closets, alcoves and stair treads. They are easy to leave off the sketch.
- Ordering from two dye lots. Shade varies between production runs exactly as it does with tile.
- Skipping the pad or reusing an old flattened one, which voids most carpet warranties.
How this carpet calculator works out its numbers
Carpet is priced by the square yard, which is exactly 9 ft². Area is length × width, plus waste, divided by 9.
- Waste defaults to 10%, which suits a room that fits a standard 12 ft roll width. Rooms 13 to 14 ft wide need a second strip that is mostly offcut, so real waste there can reach 25%.
- Carpet tile counts use true face areas: 0.25 m² for a 50 cm tile, 4 ft² for a 24 in tile, calculated in whichever unit you select rather than converted.
Figures reviewed . Every worked example on this page is checked against the calculator above.
Carpet Calculator: frequently asked questions
How many square feet in a square yard of carpet?
Nine. To convert square feet to square yards divide by 9; to go the other way multiply by 9. A 12 by 15 ft room is 180 ft², which is 20 square yards before waste.
How do I calculate square yards for carpet?
Multiply room length by width in feet for the square footage, add about 10% for seams and roll offcuts, then divide by 9. For a 12 by 15 ft room: 180 ft², plus 10% is 198, divided by 9 gives 22 square yards.
How many carpet tiles do I need?
Divide your area by the coverage of one tile and add 10%. Per 100 ft² you need about 37 tiles at 50x50 cm, 25 at 24x24 in, 36 at 20x20 in, or 44 at 18x18 in.
How wide does carpet come?
Most broadloom carpet is made on 12-foot-wide rolls, with some ranges also in 15 ft. Rooms wider than the roll need a seam and the trimmed strip is usually waste, so a 13 ft wide room can hit 25% waste rather than 10%.
Why do I need extra carpet?
Fixed roll widths leave offcuts, seams need overlap, and pile direction has to run consistently so you cannot rotate a piece to make it fit. Ten percent covers a simple room; complex or awkwardly sized rooms need more.
How much does carpet cost?
Roughly $2 to $8 per square foot for material, which is about $18 to $72 per square yard since quotes usually use yards. Installation adds around $1 to $2 per square foot and often includes removing the old floor.
Do carpet tiles waste less than broadloom?
Yes, considerably. Perimeter offcuts from one wall are usable on the opposite wall, and a damaged tile is replaced on its own rather than re-carpeting the room. That is why they dominate offices and basements.