Carpet Calculator

Carpeting a 15 ft × 12 ft bedroom means covering 180 square feet - but you should not order exactly 180. Add the standard 10% waste allowance and you are buying about 198 square feet, which is roughly 22 square yards. At a typical mid-range price of $27 per square yard ($3 per square foot), that works out to around $594 for the carpet itself. This carpet calculator does that whole conversion - area, waste, square-yard math, and cost - in one step, so you can budget a room (or a whole house) before you ever set foot in a showroom.

The formula behind the numbers

There is no mystery to it - just three short steps:

The only number people stumble on is the ÷ 9. A yard is 3 feet, so a square yard is 3 ft × 3 ft = 9 square feet. Carpet has traditionally been sold by the square yard, which is why converting matters - a price that looks high per yard can be perfectly normal per foot, and vice versa.

A worked example, start to finish

Say you are recarpeting a living room that measures 20 feet by 16 feet.

• Area: 20 × 16 = 320 sq ft.
• With 10% waste: 320 × 1.10 = 352 sq ft.
• In square yards: 352 ÷ 9 ≈ 39.1 sq yd.
• Cost at $30/sq yd: 39.1 × $30 ≈ $1,173 for the carpet.

Notice the room is 16 feet wide but carpet rolls are usually 12 feet wide. Your installer will likely run a 12-foot strip down the length and seam a second piece alongside it - which is exactly why that 10% waste cushion exists. Skip it and you risk being short by a strip you cannot color-match later.

How to measure your room

1. Measure the longest wall in feet for the length, then the longest perpendicular wall for the width. Measure to the baseboards, not the trim.
2. Round up to the nearest few inches; it is cheaper to have a little extra than to come up short.
3. Include closets and alcoves - measure each separately and add the square footage in.
4. For L-shaped or irregular rooms, split the floor into simple rectangles, find each area with the Square Footage Calculator, and add them together.
5. For doorways, carry the carpet to the center of the door or into the next room's threshold, and add that small area.
6. Sketch the room with measurements so you (or your installer) can plan where seams fall.

How to use this calculator

Enter your numbers and read the result instantly:

• Room size: type the length and width in feet, or switch to "Total area" if you already know the square footage.
• Waste: leave it at 10% for a simple room, or use the quick buttons (5/10/15/20%) for trickier layouts and stairs.
• Price: enter the carpet price and choose whether it is per square foot or per square yard - the calculator converts both ways.

The big number at the top is the total square footage to buy, with square yards and estimated cost right beneath it, plus a full line-by-line breakdown.

Who this calculator is for

• DIY homeowners pricing a single room before a store visit.
• Renovators and flippers budgeting flooring across several rooms at once.
• Landlords estimating turnover costs between tenants.
• Renters sizing area rugs or carpet tiles for a space.
• Anyone comparing quotes who wants to sanity-check an installer's square-yard estimate.

Key terms explained

• Square yard: a 3 ft × 3 ft area, equal to 9 square feet. The traditional unit for selling carpet.
• Waste factor (overage): the extra carpet, expressed as a percentage, ordered to cover trimming, seams, and roll-width mismatch. Usually 10%.
• Broadloom: carpet sold off a wide roll (commonly 12 ft) and cut to fit, as opposed to carpet tiles.
• Dye lot: a single dye batch; pieces from different lots can vary slightly in color, so buy all at once.
• Pile: the visible fibers of the carpet; pile direction affects how seams blend and how the carpet looks under light.
• Seam: where two pieces of carpet are joined, unavoidable in rooms wider than the roll.

Scenario 1: a standard bedroom

A 12 ft × 11 ft bedroom is 132 sq ft. With 10% waste that is about 145 sq ft, or roughly 16.1 square yards. At $25/sq yd the carpet runs about $403. Because the room is under 12 feet in both directions, a single roll width can cover it with minimal seaming - one of the simplest, lowest-waste jobs there is.

Scenario 2: a wide living room with a seam

An 18 ft × 14 ft living room is 252 sq ft. At 14 feet wide it exceeds the 12-foot roll, so a seam is required and 12-15% waste is wiser. At 15% that is about 290 sq ft (≈ 32.2 sq yd); at $32/sq yd the material is roughly $1,030. The extra waste pays for the seamed-in strip and a remnant for future repairs.

Scenario 3: a staircase

For a 13-step staircase, a common estimate is about 1.5-2 sq ft of carpet per step (tread plus riser). At 2 sq ft that is roughly 26 sq ft of finished area, but stairs generate heavy cutting and seaming, so apply 20% waste - about 31 sq ft. At $4/sq ft, expect around $125 in material before padding and labor. Stairs are labor-intensive, so installation often costs more than the carpet itself. If you need to nail down the tread and riser dimensions first, the Stair Calculator works those out.

What changes the result the most

• Room dimensions: the biggest driver - area grows with both length and width.
• Roll width vs. room width: a room just over 12 feet wide forces a seam and pushes up waste.
• Waste percentage: the difference between 10% and 20% is real money on a large job.
• Price unit: mixing up per-foot and per-yard pricing can make a quote look 9× off - always confirm the unit.
• Room shape: corners, closets, and irregular outlines all add cuts and waste.

Practical tips before you order

• Always order about 10% extra (more for complex rooms). Running short means a second order from a possibly different dye lot.
• Keep a remnant for repairs and patches - it will match because it is from the same lot.
• Budget for padding and labor separately; the carpet is only part of the total project cost.
• Confirm the roll width with your retailer; it determines how seams fall and how much you truly need.
• Get a professional measure for big jobs - many retailers offer it free with purchase.

Carpet fiber and style: what you are actually buying

The square footage you calculate here is the same no matter which carpet you choose, but the price per square foot or yard swings widely with the fiber and construction - which is exactly why the cost field on this calculator is yours to set. Understanding the main types helps you plug in a realistic number:

• Nylon: the most popular residential fiber. It is durable, resilient, and bounces back from foot traffic, making it a good all-rounder for living rooms, stairs, and hallways. It usually sits in the mid-to-upper price band.
• Polyester (PET): soft, stain-resistant, and budget-friendly, with rich color options. It is less resilient than nylon under heavy traffic, so it suits bedrooms and low-traffic rooms.
• Polypropylene (olefin): inexpensive and moisture-resistant, common in basements, loop-pile Berbers, and indoor-outdoor carpet, but it can crush and stain from oils more easily.
• Wool: the premium natural option - soft, naturally flame-resistant, and long-lasting, but the most expensive by a wide margin.
• Cut pile vs. loop pile: cut pile (plush, Saxony, frieze) feels soft underfoot; loop pile (Berber, level loop) is more durable and hides traffic patterns. Frieze and patterned styles hide footprints best.

When you compare quotes, make sure you are comparing the same fiber, face weight, and pile - a $2/sq ft polyester and a $6/sq ft nylon are not the same product even in the same room.

What drives the total carpet price

Two rooms of identical size can have very different bottom-line costs. The biggest levers, roughly in order of impact, are:

• Fiber and quality: wool and high-face-weight nylon cost several times more per square foot than entry-level polyester or olefin.
• Total area plus waste: the figure this calculator produces - bigger rooms and higher waste factors scale the material cost directly.
• Padding (cushion): a separate purchase, typically $0.50-$1.50 per square foot, and required under almost all stretch-in carpet.
• Installation labor: usually a few dollars per square foot for a standard room, and notably more for stairs, which are slow and cut-heavy.
• Room complexity: closets, transitions, patterns to match, and furniture moving all add labor and waste.
• Removal and disposal: tearing out and hauling away old carpet and pad is often a line item on the quote.

Because this calculator covers the carpet material only, treat its output as the foundation of the budget and then layer padding, labor, and disposal on top. For comparison shopping across flooring types, run the same room through the Tile Calculator to see how a hard-surface option stacks up.

Don't forget the padding

Carpet padding - also called cushion or underlay - is the foam, rubber, or fiber layer installed between the subfloor and the carpet. It is not optional on most jobs: the right pad extends the life of the carpet, improves comfort and insulation, and is often required to keep the manufacturer's warranty valid. Because the pad covers the same floor as the carpet, you can reuse the room area from this calculator to estimate it - just multiply your finished square footage by the pad's price per square foot (commonly $0.50-$1.50). Pad is rated by thickness and density; denser, not necessarily thicker, pad lasts longer under traffic. For stairs and high-traffic areas, installers often recommend a firmer, lower-profile pad so the carpet does not flex and wear at the edges.

Carpet vs. other flooring: a quick cost lens

If you are still weighing flooring options, carpet tends to be one of the lower upfront material costs, but the comparison depends on the room and how long you plan to stay. Carpet is warm, quiet, and forgiving on a budget, and it is the easiest soft surface to install over an imperfect subfloor. Hard surfaces such as tile, laminate, or hardwood usually cost more per square foot installed and can require subfloor prep, but they last longer and are easier to clean in kitchens, entryways, and bathrooms. A practical approach for a whole-house project is to estimate each room in its likely material: carpet here for bedrooms and stairs, and the Tile Calculator for wet and high-traffic areas. Whatever surface you choose, start from an accurate room area - the Area Calculator handles odd shapes if your room is not a clean rectangle.

Limitations and assumptions

This is a planning estimate, not a retailer quote. Keep these in mind:

• It assumes a simple rectangular area; split irregular rooms into rectangles and add them.
• It does not model roll-width layout or exactly where seams fall - a pro measure can change the quantity.
• It excludes padding, tack strips, seam tape, installation, and sales tax.
• It does not account for pattern repeat, which can require significantly more carpet to match.
• Prices vary widely by fiber, brand, and region - use a real local quote for budgeting.

Related materials & tools

Carpet is one of several flooring and material estimates you might be running on the same project:

• To find the area of any space first, use the Square Footage Calculator or the general-purpose Area Calculator.
• Comparing hard flooring instead? The Tile Calculator estimates tiles and grout for the same room.
• Carpeting a staircase? The Stair Calculator helps you work out tread and riser dimensions first.
• For volume-based materials like soil or concrete, the Cubic Yard Calculator handles the depth dimension.
• Pouring a subfloor or slab? The Concrete Calculator gives cubic yards.
• Landscaping the yard too? Try the Gravel Calculator and Mulch Calculator.
• Repainting the room before the new carpet goes down? Use the Paint Calculator.

Sources & further reading

• National Institute of Standards and Technology (NIST) - unit conversion reference for the foot-to-yard and square-foot-to-square-yard math (1 sq yd = 9 sq ft).
• Roll-width, waste, dye-lot, and installation conventions reflect standard U.S. broadloom retail and installation practice.