How Much Carpet Do I Need?

Calculate carpet needed for one room or multiple rooms. Includes waste factor for cuts and seams.

How to Calculate Carpet

Multiply room length by width to get square footage. Add 10% for waste. Divide total square feet by 9 to convert to square yards — the standard unit carpet is sold in. Example: a 12×14 ft bedroom = 168 sq ft. With 10% waste = 185 sq ft ÷ 9 = 20.6 → order 21 square yards.

Carpet comes in standard roll widths of 12 feet (and sometimes 15 feet). If your room is wider than 12 feet, you'll need a seam — this adds to waste and cost. A 14×16 room requires two widths of 12-ft carpet to cover the 14-ft dimension, meaning you're paying for more carpet than you need on one side.

Ordering Off the Roll: 12 ft vs 15 ft Width

Square yards with a waste factor are a budgeting number. What the store actually cuts is a length off a roll that is 12 feet wide (most carpet) or 15 feet wide (some styles), and you pay for the full width of every strip whether the room uses it or not. That is why the result box above also lays each room out on both roll widths, in whichever direction uses less carpet, with 3 inches of trim allowance at each end of every strip.

The roll width can matter more than the waste percentage. A 14x15 room fits on one 14 ft 6 in strip of 15 ft carpet, about 24 sq yd with no seam. On 12 ft carpet it needs two strips and a seam, about 39 sq yd, because the second strip is mostly offcut. An 18 ft by 21 ft 9 in room goes the other way: on a 12 ft roll it is two strips of 18 ft 6 in (37 linear feet, about 49 sq yd), while on a 15 ft roll the same two strips come to about 62 sq yd.

Two practical checks before ordering. If a room is within an inch or two of the roll width, measure that wall in several places, because walls are rarely straight enough to fit without a fill strip. And when you have several small rooms, tell the installer: offcuts from a long strip often cover a closet or landing, which can save a separate cut.

Carpet Types and What They Cost

Installation labor adds $3–$8 per square yard on top of material cost. Most installers charge a minimum of $100–$200 for small jobs. Moving furniture is sometimes included, sometimes extra — confirm before booking.

Carpet Padding: Don't Skip It

Carpet padding is installed under the carpet and is not optional — it extends carpet life by absorbing foot traffic stress, improves comfort underfoot, and provides thermal and sound insulation. Standard padding runs $0.50–$1.50 per square foot (not yard). Premium memory foam padding costs $1.50–$3.00 per square foot and makes a noticeable difference in feel.

Thicker padding (7/16") is softer underfoot; thinner padding (3/8") is recommended for Berber and loop-pile carpets, which can stretch and wrinkle over thick padding. Your carpet manufacturer's warranty usually specifies a maximum padding thickness.

Broadloom Carpet vs. Carpet Tiles: Which Should You Choose?

This calculator estimates broadloom carpet by the square yard. If you're comparing carpet tiles instead, see our carpet tile installation guide — tile counts are figured per-piece rather than by yardage, since waste and seam rules don't apply the same way.

Common Carpet Ordering Mistakes

• Forgetting stairs — Each stair step typically needs about 1.5–2 sq yd of carpet depending on tread and riser depth. Room-based quotes routinely leave stairs out entirely.
• Ignoring nap direction — Carpet pile has a directional "nap," similar to fabric grain. Pieces installed with mismatched nap direction show visible color and shading differences under light, even from the same dye lot.
• Ordering exact yardage instead of roll increments — Carpet is cut from 12-ft-wide rolls in linear-foot increments. A calculation that lands just over a foot mark can force you to pay for a whole extra linear foot (12 sq ft) you didn't plan for.
• Not measuring closets separately — As covered in the FAQ below, forgotten closets are one of the most common reasons people run short on carpet mid-install.

Frequently Asked Questions

Should I buy 12 ft or 15 ft wide carpet?

Whichever lets each room fit in fewer strips. A room up to 12 ft wide fits one strip of 12 ft carpet; a room 12 to 15 ft wide fits one strip of 15 ft carpet but needs two of 12 ft carpet. For a 14x15 room the 15 ft roll needs about 24 sq yd against about 39 sq yd on a 12 ft roll.

How do I figure how many linear feet of carpet to order?

Decide which way the strips run, divide the room's other dimension by the roll width and round up to get the number of strips, then multiply by the run length plus about 6 inches for trimming. An 18 ft by 21 ft 9 in room on 12 ft carpet is two strips of 18 ft 6 in, or 37 linear feet.

How many square yards of carpet do I need for a 12x14 room?

A 12x14 ft room = 168 sq ft. With 10% waste = 185 sq ft. Divide by 9 = 20.6 square yards. Order 21 square yards to be safe.

Why is carpet sold in square yards instead of square feet?

Carpet has been sold by the square yard as an industry standard for decades. To compare prices, divide the square yard price by 9 to get the per-square-foot equivalent.

How much extra carpet should I order for waste?

Add 10% waste for simple rectangular rooms under 12 feet wide. Add 15% for rooms requiring seams (over 12 feet wide) or L-shaped rooms. Add 15–20% for patterned carpet that must align at seams.

What is the 12-foot roll width rule for carpet?

Carpet typically comes in 12-foot wide rolls. If your room is wider than 12 feet, a seam is required — and you pay for the full 12-foot width on both sides of the cut, which increases waste significantly.

Do I need to include closets when ordering carpet?

Yes. Measure closets separately and add them to the room total before calculating. Forgotten closets are one of the most common reasons people run short on carpet.