🧶 Carpet Calculator
By ToolNimba Construction Team · Updated 2026-06-19
Carpet is usually sold by the square yard (1 sq yd = 9 sq ft). The figures above are the bare floor area plus your waste allowance, which covers offcuts, pattern matching and seams. They do not include stairs, closets or doorways unless you enter them as extra rooms. Always confirm the final quantity with your installer before ordering.
This carpet calculator works out how much carpet you need and roughly what it will cost. Enter the length and width of each room, add more rooms if you have them, set a waste allowance (10% is a sensible default), and the tool shows the floor area in both square yards and square feet, with and without waste. Add a price per square yard, square foot or square metre and it estimates the total cost too.
What is the Carpet Calculator?
Carpet is bought to cover a floor area, so the core calculation is simply length times width for each room, added together. The catch is the units. Floor space is easy to picture in square feet (length in feet times width in feet), but carpet has traditionally been sold by the square yard, and a square yard is a 3 ft by 3 ft square, which is 9 square feet. To convert, you divide the square footage by 9. A 12 ft by 10 ft room is 120 square feet, which is 120 ÷ 9 = 13.33 square yards.
Real installations always need more material than the bare floor area. Carpet comes off a roll in a fixed width (commonly 12 ft, sometimes 13 ft 6 in or 15 ft), so a fitter has to cut pieces that rarely line up perfectly with your room. Doorways, alcoves, stairs and pattern matching all create offcuts that cannot be reused. That is what the waste allowance covers. A simple rectangular room might need only 5% to 10% extra, while rooms with many corners, a bold repeating pattern, or stairs can push the allowance to 15% or 20%. The figure here is an estimate to budget with, not a cutting plan.
Cost follows directly once you know the quantity. If carpet is priced per square yard, multiply the square yards (including waste) by the price. If it is priced per square foot or per square metre, the tool uses the matching area. Remember the sticker price is usually just the carpet itself. Underlay (padding), gripper rods, door bars, delivery and fitting are extra, and many retailers quote those separately, so add them on before you compare quotes.
When to use it
- Working out how many square yards of carpet to order for a single room before visiting a flooring store.
- Adding up several rooms (lounge, hallway, bedrooms) to get one total area and one budget figure.
- Comparing two carpets priced differently (one per square yard, one per square metre) on the same floor.
- Sanity-checking an installer quote so you know whether the quantity and the waste allowance look reasonable.
How to use the Carpet Calculator
- Choose whether you are measuring in feet or meters.
- Enter the length and width of your first room.
- Click "Add room" for each additional space and enter its dimensions.
- Set a waste allowance (10% is a common starting point).
- Optionally enter the carpet price and pick whether it is per square yard, foot or metre.
- Read off the carpet needed in square yards and square feet, plus the estimated cost.
Formula & method
Worked examples
A single 12 ft by 10 ft bedroom, with a 10% waste allowance, carpet at $25 per square yard.
- Floor area = 12 × 10 = 120 sq ft
- In square yards = 120 ÷ 9 = 13.33 sq yd
- With 10% waste = 13.33 × 1.10 = 14.67 sq yd (132 sq ft)
- Cost = 14.67 × 25 = 366.67
Result: Order about 14.67 sq yd (132 sq ft), costing roughly $366.67 for the carpet.
Two rooms in metric: a 4 m by 5 m lounge and a 3 m by 4 m bedroom, with a 10% waste allowance.
- Lounge area = 4 × 5 = 20 sq m, bedroom = 3 × 4 = 12 sq m
- Total = 32 sq m
- In square feet = 32 × 10.7639 = 344.45 sq ft
- In square yards = 344.45 ÷ 9 = 38.27 sq yd
- With 10% waste = 38.27 × 1.10 = 42.10 sq yd (378.89 sq ft)
Result: Order about 42.10 sq yd (378.89 sq ft) of carpet for the two rooms.
Floor area to square yards (before waste), for common room sizes in feet
| Room size | Square feet | Square yards | With 10% waste (sq yd) |
|---|---|---|---|
| 10 × 10 ft | 100 sq ft | 11.11 sq yd | 12.22 sq yd |
| 12 × 10 ft | 120 sq ft | 13.33 sq yd | 14.67 sq yd |
| 12 × 12 ft | 144 sq ft | 16.00 sq yd | 17.60 sq yd |
| 15 × 12 ft | 180 sq ft | 20.00 sq yd | 22.00 sq yd |
| 20 × 15 ft | 300 sq ft | 33.33 sq yd | 36.67 sq yd |
Suggested waste allowance by room type
| Situation | Typical waste allowance |
|---|---|
| Simple rectangular room | 5% to 10% |
| Room with alcoves or many corners | 10% to 15% |
| Patterned carpet (repeat matching) | 10% to 20% |
| Stairs and landings | 15% to 20% or more |
Common mistakes to avoid
- Confusing square yards with square feet. A square yard is 9 square feet, not 3. Ordering "120 square yards" for a 120 square foot room would buy nine times too much carpet. Always divide square feet by 9 to get square yards.
- Ordering the exact floor area with no waste. Carpet comes off a fixed-width roll, so offcuts are unavoidable. Buying the bare floor area leaves you short once the fitter trims pieces to fit. Add at least 5% to 10%, more for patterns or odd shapes.
- Forgetting closets, doorways and bay windows. Small recesses still need carpet. Measure into closets and doorways, or add them as extra rooms here, so the total reflects the whole floor you are covering.
- Comparing carpets on price per unit alone. One shop may quote per square yard and another per square metre or square foot. Convert to the same unit before comparing, and remember underlay, gripper and fitting are usually extra.
Glossary
- Square yard
- A 3 ft by 3 ft square, equal to 9 square feet. The traditional unit carpet is sold by.
- Square foot
- A 1 ft by 1 ft square. Floor area in feet is length times width in feet.
- Waste allowance
- Extra carpet added to the floor area to cover offcuts, seams and pattern matching, given as a percentage.
- Roll width
- The fixed width carpet is manufactured in (often 12 ft), which drives how much waste a room produces.
- Underlay (padding)
- The cushioning layer fitted beneath carpet. It is bought separately and is not part of the carpet area price.
Frequently asked questions
How much carpet do I need for a room?
Multiply the room length by its width to get the floor area, then divide square feet by 9 to get square yards. Add a waste allowance of about 10% for a simple room. This calculator does all three steps and shows the result in both square yards and square feet.
How do I convert square feet to square yards?
Divide the number of square feet by 9, because one square yard (3 ft by 3 ft) equals 9 square feet. For example, 180 square feet is 180 ÷ 9 = 20 square yards.
How much waste should I allow for carpet?
For a simple rectangular room, 5% to 10% is usually enough. Allow 10% to 15% for rooms with many corners or alcoves, and up to 20% or more for patterned carpet that needs matching, or for stairs. The default here is 10%.
Does the carpet area cost include fitting and underlay?
No. The cost shown is only the carpet itself, based on the price per unit you enter. Underlay (padding), gripper rods, door bars, delivery and fitting are usually charged separately, so add those before comparing total quotes.
Can I calculate several rooms at once?
Yes. Click "Add room" for each space and enter its length and width. The calculator sums the areas and gives one total in square yards and square feet, plus a single cost estimate.
Why does the store measure in square yards but I measured in feet?
Carpet has long been sold by the square yard, while most people measure rooms in feet or metres. They describe the same area in different units: divide square feet by 9 for square yards, or multiply square metres by about 1.196 for square yards.