Carpet Calculator

The short answer

Carpet is sold by the square yard, and a 12 by 14 foot room is 168 square feet — 18.7 square yards. Adding 10% for cutting, seaming and pattern repeat brings the order to about 21 square yards. Because carpet comes in 12-foot widths, a room wider than 12 feet needs at least one seam, and a seam's position is a layout decision rather than an afterthought.

What it depends on

Pattern repeat is the biggest hidden variable: a large or complex repeat can add 15 to 25% to the material needed compared with a plain carpet of the same area. Pile direction affects both appearance and wear, and running pile in different directions between pieces shows a visible shade difference. Stairs need extra calculated by tread and riser, not by area.

Where this stops being useful

This is a quantity estimate and does not price the carpet, pad or installation, all of which vary widely by quality and region. Subfloor condition, moisture and door clearances can change the scope. A retailer's measure is the authoritative figure for an order. General information and planning only, not engineering, structural or code advice.

The main trap is the pattern repeat. A patterned carpet has to match across every seam, and matching wastes more material than a plain one — often ten percent on a simple layout and more where the repeat has to line up on a stair or around a bay window. Seams also have to be placed where furniture will sit, because a visible join in an open area looks like an error. Where the carpet runs up a stair, add the tread depth times the number of steps, and note that stair carpet is normally cut to fit rather than stretched.

Carpet is also the item most often included as an afterthought and most often replaced after it is fitted, because the colour or the pile was not thought through at the ordering stage. The calculation is straightforward; the decision it supports is not, which is why it is worth doing before the order rather than during it.

Carpet is sold by the square yard, so divide the area by nine after your waste allowance and round up. Underlay is measured the same way and is worth ordering at the same time, because suppliers frequently discount a combined order. Ask about remnant pricing if your area is small — many stores sell offcuts from a previous roll at a large discount, and a bedroom is often big enough. Order a little more than you think you need; leftover carpet can be patched from a remnant later, whereas running short means a second delivery fee.

Carpet is usually priced by the square yard, though rooms are measured in feet, and the direction the pile runs means a room cannot always be covered with one seamless piece. These two facts explain why a carpet estimate is rarely just the floor area: you pay for the carpet that must be cut and thrown away to make the seams and edges work. Roll width drives the layout. Carpet comes in fixed widths, typically twelve or fifteen feet, and the backing has a direction, so pieces must be laid the same way up. In a room wider than the roll, a seam is unavoidable and the two pieces must be matched, which wastes material along the join. Fitters measure the longest run in both directions and buy enough length to cover the room including the seam allowance. Waste also comes from doorways and irregularities. A bay window, a chimney breast or a run of fitted wardrobes all create awkward cuts. Ten per cent on top of the measured area is a common working allowance for a simple room; more complex shapes, stairs and landings push it higher. Stairs in particular consume more carpet than their plan area suggests, because each tread and riser is a separate cut. This calculator turns the room dimensions into square feet and square yards with a waste allowance, and applies a price if you enter one. It covers the carpet itself, not underlay, gripper or fitting, which together often cost a meaningful fraction of the total. Measure your room carefully, then confirm the roll width and seam plan with your fitter.

This calculator returns estimates for planning and general information only. It is not engineering, architectural, structural, electrical or code advice, and it cannot replace a qualified professional who has seen the site. Material quantities depend on the actual dimensions, the product you buy and local building codes, so confirm the figures before ordering materials or starting work, and always follow local regulations.