Carpet Calculator
Estimate carpet square feet, square yards, roll length, stairs, carpet pad, waste, and optional material or installation cost.
This page is for roll carpet, pad, stairs, and rough carpet install estimates. For laminate, LVP, hardwood, or engineered flooring boxes, use the Flooring Calculator.
Results
This is a carpet material and rough cost estimate. Final installer measurements can change because of seams, pattern direction, transitions, stairs, and room layout.
How to use this calculator
- 01Pick Room, Known Area, or Stairs.
- 02Enter the room dimensions, known area, or stair width, tread, riser, and count.
- 03Choose a carpet roll width and add a waste or seam allowance.
- 04Turn on carpet pad if you are ordering separate pad.
- 05Open Add cost estimate only if you want rough carpet, pad, or installation cost.
For irregular rooms, split the floor into rectangles or check the area first with the Square Footage Calculator.
Understanding the math
Carpet quantity starts with area. For rooms, area is length times width. For stairs, each step uses stair width times tread plus riser.
room_area = length x width stair_area = width x (tread + riser) x stair_count
carpet_needed = area x (1 + waste_percent / 100) square_yards = carpet_needed / 9 roll_length = carpet_needed / roll_width
carpet_cost = carpet_area_with_waste x carpet_price pad_cost = pad_area x pad_price install_cost = base_area x install_price
Carpet seams, pattern direction, room transitions, stairs, and installer layout can change the final order quantity. Use this as a planning estimate, then confirm with the installer or supplier before ordering.
Carpet reference
Common roll widths, square yard conversion, and stair measuring notes. Values follow the active unit system where practical.
| Reference | Value | Use |
|---|---|---|
| 12 ft roll | Common width | Typical residential carpet |
| 13 ft 6 in roll | Wider option | Can reduce seams |
| 15 ft roll | Widest common roll | Useful for large rooms |
| 1 sq yd | 9 sq ft | Carpet yardage conversion |
| Waste/seams | 5-15% | Higher for cuts or seams |
| Stairs | width x (tread + riser) | Per step before waste |
Frequently asked questions
How do I calculate how much carpet I need?
Measure the carpet area, add a waste or seam allowance, convert to square yards, and check the roll length from the roll width. Irregular rooms can be split into smaller rectangles and added together.
How do you calculate square feet for carpet?
For a rectangle, multiply room length by room width. For multiple rooms, calculate each area and add them together. For irregular rooms, use the Square Footage Calculator first, then enter the total area here.
How to calculate carpet for stairs?
Use stair width times tread depth plus riser height, then multiply by the number of stairs and add waste.
How to calculate yardage for carpet?
Divide square feet by 9 to get square yards. If waste is included, convert the carpet area after waste.
How much would it cost to carpet a 2000 sq ft house?
Cost depends on carpet price, pad, installation rate, waste, seams, stairs, removal, and local labor. Enter local material, pad, and install rates for a rough estimate; it is not a final contractor quote.
Is carpet sold by square foot or square yard?
Both are common. Many estimates show square feet, while carpet is often discussed in square yards. This calculator shows both where useful.
Can I use this calculator with metric measurements?
Yes. Use the Imperial/Metric toggle. Inputs, results, reference values, and examples follow the active unit system where applicable.
Related calculators
Flooring Calculator
Estimate boxes, waste, underlayment, and material cost for laminate, LVP, hardwood, and engineered flooring.
Square Footage Calculator
Calculate room, wall, floor, or project area from length and width before estimating materials.
Stair Calculator
Calculate stair rise, run, stringer length, and tread count for residential stairs.