Carpet Calculator

The carpet calculator answers the most common flooring question: how many square yards (or square meters) of carpet do I need to finish a room? Enter your room's length and width, pick a waste percentage based on the carpet style, and the calculator computes total floor area, carpet needed with waste, padding required, and optional total cost. The output shows three units simultaneously — square feet, square yards and square meters — so you can match the unit your supplier quotes (US dealers price per sq yd, UK and Australian retailers price per sqm, Canadian suppliers use both). Use it for any rectangular room: bedrooms, living rooms, basements, offices, hallways, apartments and commercial spaces. For L-shaped or irregular rooms, divide the floor into rectangles, calculate each separately, and sum the carpet requirements before placing your order.

Step 1: Measure the room. Use a tape measure or laser distance meter for length and width in feet (US/CA) or meters (UK/AU). For a 12 × 15 ft bedroom, record length = 15, width = 12. Step 2: Calculate floor area. Length × width = floor area. 15 × 12 = 180 sqft (20 sq yd or 16.7 sqm). Step 3: Apply waste factor. Pick the right percentage for your carpet style: 10% for solid colors and plain Berber, 15% for patterned or striped, 20%+ for diagonal layouts or stairs. 180 × 1.10 = 198 sqft. Step 4: Convert to your supplier's unit and order. 198 sqft = 22 sq yd or 18.4 sqm. Round up to half-yard or whole-meter increments depending on the showroom's pricing. The calculator above does all four steps automatically and shows results in every unit at once.

The biggest source of carpet ordering errors is unit confusion. United States carpet trade convention: quote per square yard ($X per sq yd). Room dimensions are measured in feet, so you must divide sqft by 9 to get sq yd. A 12 × 15 ft room = 180 sqft = 20 sq yd. United Kingdom and Australia: quote per square meter (£X per sqm or A$X per sqm), with rooms measured in meters. A 3.66 × 4.57 m room = 16.7 sqm. Canada: mixed convention — many retailers quote sq yd to match US pricing, others have switched to sqm. Always confirm the unit when comparing quotes, and use the calculator's simultaneous three-unit output to cross-check. Conversion: 1 sq yd = 9 sqft = 0.836 sqm; 1 sqm = 10.764 sqft = 1.196 sq yd.

Waste percentage isn't a one-size-fits-all default — it depends on the carpet style and installation context. Plain solid color or plain Berber: 10% waste — any off-cut works anywhere on the floor, no pattern matching required. Light pattern or stripes (linear, repetitive): 12-15% waste — stripes must align across seams and at perimeters, off-cuts that don't match the run get trimmed. Bold pattern or geometric (florals, large-scale designs): 15-20% waste — every seam needs pattern match, off-cuts smaller than the repeat unit are unusable. Diagonal or herringbone installation: 20-25% waste — diagonals cut corners aggressively from a rectangular roll. Stairs and tight winding spaces: 20-25% waste — stair wraps require specific cuts plus padding-stretch overlap. Commercial broadloom over large open floors: 18-25% waste depending on pattern repeat. Always ask your supplier the pattern repeat dimension (typically 12-36 inches) before settling on a waste percentage.

Padding (also called underlay or cushion) is the cushioned layer installed under carpet — essential for comfort, sound insulation and carpet warranty compliance. Padding sizing is straightforward: total room area without a waste factor, since padding is installed in any shape and off-cuts at walls are reusable. A 180 sqft room needs 180 sqft of padding (20 sq yd or 16.7 sqm). Padding is sold separately from carpet, typically $4-8 per sq yd in the US, £4-6 per sqm in the UK, $5-9 CAD per sq yd in Canada, A$8-15 per sqm in Australia. Standard residential padding is 8 lb (3.6 kg) density rebond at 7/16 in (11 mm) thickness; high-traffic areas use 10 lb density. Commercial padding is denser and thinner. Most carpet warranties require approved padding installed by the same contractor — DIY padding installation can void the carpet warranty.

Whole-house carpet projects need a room-by-room calculation, then a continuity decision. For each room, measure length × width and apply the appropriate waste factor — keep results in the same unit (preferably sq yd for US/CA or sqm for UK/AU). Then decide: order separately by room, or order one continuous run to share a single dye lot across rooms? Continuous runs guarantee color match across rooms but require larger upfront ordering and may waste more carpet from a single roll. Separate orders risk dye lot differences but reduce waste. For most whole-house residential projects (3-5 bedrooms plus hallways), continuous-run ordering with 12-15% combined waste is recommended. Hallways and stairs typically need 5-10% extra waste because of stretch transitions and stair wraps. Sum all rooms, apply combined waste, and verify the total against a single carpet roll's coverage (typically 720 sqft / 80 sq yd / 66.9 sqm per 12 ft × 60 ft roll).

Stairs use significantly more carpet per linear foot than flat rooms because each step wraps both the tread (horizontal surface, ~10-12 in) and the riser (vertical surface, ~7-8 in). Industry rule of thumb: add 0.5 sq yd (0.42 sqm) per stair step on top of the connected room area. A typical 13-stair flight from one floor to the next adds 6.5 sq yd (5.4 sqm). Wider staircases (over 36 in / 91 cm) need proportionally more — measure each tread depth, riser height and width, then multiply for total stair surface. Stair installations also need a higher waste factor (20-25%) because of the wrap cuts and the difficulty of using off-cuts elsewhere. Open stringers (visible side of the stair) need wrap-around carpet, adding 25-50% extra carpet per stair. Hire a professional installer for stairs — DIY installation has safety risks if the carpet isn't tightly anchored, and most regional building codes require pro installation for rental properties.

Carpet style affects price, durability, comfort and waste percentage. Berber: low-pile looped construction, durable, moderate price ($20-40 per sq yd), 10-12% waste, snags if pets' claws get caught — best for low-to-medium traffic. Plush (cut-pile): soft uniform surface, shows footprints and vacuum tracks, moderate-to-high price ($25-50 per sq yd), 10% waste — best for bedrooms and formal living rooms. Saxony (cut-pile, longer fiber): soft luxurious feel, premium price ($30-60 per sq yd), 10-12% waste, crushes in high-traffic — best for low-traffic bedrooms. Frieze (twisted cut-pile): textured surface hides wear and footprints, moderate-to-premium price ($25-45 per sq yd), 10% waste — best for family rooms and high-traffic areas. Pattern loop or cut-and-loop combinations: textured look, mid-to-premium price ($30-60 per sq yd), 15-20% waste due to pattern match. Commercial-grade loop (Heavy Traffic): durable, plain or subtle pattern, $20-45 per sq yd, 12-18% waste. Pick the style first, then apply the correct waste factor.

Total carpet project cost is the sum of three line items: carpet material, padding, and installation labor. Material cost = carpet area (with waste) × price per sq yd or sqm. Padding cost = room area (no waste) × padding price. Installation cost = room area × labor rate. Typical US ranges for a residential bedroom (180 sqft / 20 sq yd / 16.7 sqm): carpet at $30 per sq yd × 22 sq yd = $660; padding at $5 per sq yd × 20 sq yd = $100; installation at $4 per sq yd × 20 sq yd = $80; total = $840 before taxes and add-ons. Add-ons that increase cost: removal of old carpet ($1-2 per sq yd), furniture moving ($30-60 per room), stair installation ($5-8 per stair), transition strips at doorways ($10-20 each), pattern match labor for patterned carpet (+15-25% to installation). UK equivalent: convert price-per-sq-yd to price-per-sqm by dividing by 1.196 — a $30 per sq yd carpet is roughly £25 per sqm. Use the calculator's pricing fields to enter local rates and get exact project cost.

Six mistakes that cause running short or massively overbuying carpet. (1) Wrong waste factor for the pattern — using 10% on patterned carpet that actually needs 15% shortens the order by 5% and forces re-ordering, possibly from a different dye lot. (2) Unit confusion — quoting per sq yd to a UK supplier or per sqm to a US dealer leads to 8-9× over- or under-ordering. Always confirm the unit. (3) Forgetting closet area — a typical bedroom has 30-50 sqft of closet that gets carpeted with the room; not including it means short order. (4) Skipping the stair adjustment — stairs use ~0.5 sq yd per step on top of the room calculation. (5) Round down instead of up — carpet is sold in half-yard increments at minimum; rounding 20.1 sq yd down to 20 sq yd creates a 0.1 sq yd shortage. Always round up. (6) Not noting the dye lot number — installing carpet from two different lots in the same continuous run shows subtle color shift in daylight; record the lot number from each roll label before installation. The single biggest accuracy improvement: measure twice, pick the right waste factor, and round up.

Carpet installation is one of the more complex DIY flooring projects — even simple rooms benefit from professional installation in many cases. DIY is realistic when: the room is rectangular with no seams (typical bedroom or study under 12 × 12 ft), the carpet is solid color or plain Berber (no pattern match), you have access to a carpet kicker or power stretcher (rental $25-50 per day), and the substrate is clean and ready. Hire a professional when: the room is over 12 × 12 ft and requires a seam (seaming is craft-skill work — bad seams show forever), the carpet is patterned (pattern match across seams requires experience), the project includes stairs (safety concerns plus stair-wrap technique), the carpet has a warranty that requires certified installation (many premium warranties), or it's a commercial space (building codes typically require pro installation for rentals and businesses). Professional installation in the US typically costs $3-8 per sq yd; in the UK £3-5 per sqm; in Australia A$8-15 per sqm; in Canada $4-6 CAD per sq yd. Worth the cost on anything more complex than a single rectangular bedroom.

Quick mental math for carpet shopping. Bedroom (12 × 14 ft, plain): 168 sqft = 18.7 sq yd = 15.6 sqm → order 21 sq yd with 12% waste. Bedroom (12 × 14 ft, patterned): same area → order 24 sq yd with 15% waste. Master bedroom (14 × 16 ft, plain): 224 sqft = 24.9 sq yd → order 28 sq yd. Living room (16 × 20 ft, plain): 320 sqft = 35.6 sq yd → order 40 sq yd. Living room (16 × 20 ft, patterned): same area → order 42 sq yd. Family room (18 × 22 ft, frieze): 396 sqft = 44 sq yd → order 49 sq yd with 12% waste. Hallway (4 × 20 ft, plain): 80 sqft = 8.9 sq yd → order 10 sq yd with 12%. Stairs (13 steps, runner): 6.5 sq yd → order 8 sq yd with 25% waste. Whole 3-bedroom 1,200 sqft house carpet: typically 145-160 sq yd including hallways and master closet. Always: round up, confirm the dye lot, save a roll-end for repairs, and verify the unit your supplier quotes. Use the calculator above for project-specific numbers; this cheat sheet is for ballpark estimates when you're scoping work.