How do I calculate carpet for a room?

Multiply the room length by the room width in feet to get the square footage, then divide by 9 to convert to square yards. Carpet is typically sold by the square yard, so this gives you the base amount needed before adding waste.

How much extra carpet should I order?

Add 10-15% extra carpet for waste, seams, pattern matching, and cuts around doorways and closets. Complex room shapes or patterned carpet may require up to 20% extra to ensure proper alignment.

What is the standard carpet roll width?

Standard carpet rolls come in 12-foot and 15-foot widths. Choosing the right roll width for your room dimensions can minimize seams and reduce waste, which saves money on larger installations.

How do I calculate carpet for stairs?

Measure the depth of one tread plus the height of one riser, add 2 inches for the nose tuck, then multiply by the number of stairs. Standard stairs need about 36 inches of carpet width per stair.

Why is carpet sold by the square yard?

Carpet has been priced per square yard for over 100 years — it's the industry convention. 1 square yard = 9 square feet. A 12-foot × 14-foot room (168 sq ft) is 18.67 square yards. Most US retailers will quote per sq ft on consumer-facing materials but per sq yd on bid sheets. Always confirm the unit when comparing quotes — a $20/yd carpet vs $20/sq ft carpet is a 9x cost difference.

How much waste should I add when ordering carpet?

Standard waste: 10% for simple rectangular rooms with single-pattern carpet. Add 15-20% for patterned carpet (requires pattern matching), Berber loop (more careful seaming), or rooms with multiple doorways/closets. Stairs and irregular spaces require 20-25% waste. Always order full extra width — 12-foot rolls cannot be efficiently split for a partial width.

What's the difference between 12-foot and 15-foot carpet rolls?

12-foot is the industry standard width — covers most rooms with one piece. 15-foot is increasingly common for wider rooms (15+ feet) where 12-foot would require a visible seam. 15-foot carpet costs 10-20% more per sq yard but eliminates the seam in mid-sized rooms. Some manufacturers also offer 13-foot, 13'2", and 13'6" widths — always confirm the actual width with your supplier before ordering.

Do I need carpet padding?

Yes — padding is required for proper carpet installation. It extends carpet life by 50-100%, provides cushioning, improves insulation, and is required by most carpet warranties. Standard residential padding is 6-7 lb density × 3/8" thick ($0.40-$0.80/sq ft). Premium memory-foam pads are $1.50-$3/sq ft. Skipping padding voids warranties on most carpet products.

How long does carpet installation take?

Experienced installer averages 40-50 sq yards (360-450 sq ft) per day solo. Two-person crew: 80-100 sq yards per day. Pattern-match carpet, stairs, and complex layouts cut speed by 30-50%. A typical 1,500 sq ft house (167 sq yards) is a 1-2 day job for a single installer, or a single day for a 2-person team. Add 1-2 hours for moving furniture if the homeowner hasn't done it.

Carpet Calculator

Calculate the exact amount of carpet, padding, and linear footage you need from the roll. Supports multiple rooms, seam placement, and both 12-foot and 15-foot roll widths — so you order the right amount and minimize waste.

Room Dimensions

Room Name

Length (ft)

Width (ft)

Carpet Roll Width

Seam Direction

Seams run parallel to this direction. Roll covers 12 ft in the perpendicular direction.

Waste Factor (%)

10% is standard. Use 15% for patterned carpet or irregular rooms.

Include Padding

Price Per Sq Ft ($) — optional

Carpet Estimate

Total Area

132

sq ft (incl. 10% waste)

Carpet to Order

14.7

sq yards

Linear Feet from Roll

from 12 ft wide roll

Total Seam Length

linear feet of seams

Padding Needed

132

sq ft

Seam Count

across all rooms

Accessories Shopping List

Tack strip (4-ft pieces)

11 pcs~41 linear ft

Doorway transitions (metal Z-bar or similar)1

Estimated installer-days (1 installer)1 day

Pro Tips

Order one full extra strip beyond the calculation on jobs with seams. Carpet from different dye lots is virtually impossible to match if you run short mid-install.
Run seams parallel to the main light source (window) when possible — perpendicular seams catch shadows and are noticeably more visible.
Pattern-match carpet adds 15-25% waste beyond standard. The waste factor in this calculator assumes solid or randomly-textured carpet. Bump waste to 20-25% for Berber or any patterned product.
Tack strip pricing: $1-$2 per 4-ft piece. You typically need slightly less than the perimeter (subtract doorways and built-ins). Concrete subfloors need tack strip with masonry nails; wood subfloors use standard.
Heat-activated seam tape(vs cold-pressed) is the modern standard. Requires a seam iron rental (~$15/day) for proper install — don't cheap out on the seam — it's the most common warranty callback.
Padding sold separately by retailer.Some retailers bundle, most quote separately. Standard residential padding is 6-7 lb density × 3/8" thick at $0.40-$0.80/sq ft. Premium memory-foam pad runs $1.50-$3/sq ft.

Did this help?

How to Use This Calculator

Add each room with its length and width in feet. Select your carpet roll width (12 ft is standard; 15 ft reduces seams in wider rooms). Choose the seam direction — running seams along the longer dimension usually looks best and reduces visibility. Adjust the waste factor for irregularly shaped rooms or pattern-match carpet. Toggle padding on or off. Optionally enter a price per square foot to get a cost estimate.

Formula Used

Total Area = Sum of (Length × Width) per room. Sq Yards = Total Area × (1 + Waste%) / 9. Linear Feet from Roll = Strips × Run Length per room, where Strips = ceil(Cross Dimension / Roll Width). Seam Length = (Strips − 1) × Run Length.

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Disclaimer

This calculator is for estimation purposes only. Results may vary based on local conditions, materials, and building codes. Always consult a licensed professional before making decisions based on these calculations. MyContractorTools is not responsible for any errors or omissions.