Flooring Calculator

The short answer

A 12 by 14 foot room is 168 square feet, and at a 10% waste allowance the order is about 185 square feet. Most boxes cover 20 square feet, so that is nine and a quarter boxes — order ten. The waste allowance is not padding: it covers cuts at the walls, the first and last rows, and any damaged pieces.

What it depends on

Layout changes the waste factor substantially. A straight lay needs 5 to 10%; a diagonal or herringbone layout needs 15% or more because of the angle cuts and the increased offcut waste. Room shape matters more than area — a long narrow room with many doorways and a chimney breast wastes more than a square of the same size. Batch matching is the other reason not to under-order.

Where this stops being useful

This is a quantity estimate and does not cover underlayment, transitions, thresholds, trim or removal of the existing floor, all of which add cost. Subfloor flatness and moisture are the usual causes of failure, and both need checking before installation. A retailer's measure is authoritative for an order. General information and planning only, not engineering, structural or code advice.

Board direction and pattern matching both affect how much you need. Staggering a plank floor means the offcut from each row lands at the far end, so you add the length of the longest plank to the waste allowance. A herringbone or chevron pattern wastes far more — often fifteen percent or more — because the diagonal cuts generate small unusable triangles. If the room has a complicated shape, lay it out on paper first and count what you would actually cut, rather than trusting a percentage.

Flooring is one of the few jobs where the layout can be decided before anything is bought, and that decision is worth more than any percentage allowance. Ten minutes with a plan and a pencil on a large floor will save the cost of a box, and on a bigger room considerably more than that.

Order the floor in one delivery if you can. Colour variation between batches is normal in natural materials, and a room that spans two batches can show a visible line where they meet. When you calculate the cost, remember that flooring is priced either per square metre or per square foot and that boards are sold in fixed lengths, so the area figure and the purchase figure differ. Use this calculator for the area and the waste, then confirm the number of boxes with the supplier before paying — they will often check your figure and tell you if you are short.

Laminate, vinyl plank and engineered wood are sold by the box, and every box states the area it covers. The estimate is therefore a simple area calculation followed by a division — but only if you allow properly for waste, which is where most DIY flooring jobs come up short. Buying a box too few mid-install is frustrating, because the same batch may no longer be available and shades can differ between production runs. Waste depends on the layout. A rectangular room with planks running parallel to the longest wall gives the least waste; planks laid diagonally, herringbone patterns or a room full of doorways and alcoves waste much more. Ten per cent suits a simple room, while fifteen per cent is wiser for anything with a pattern, a diagonal run, or lots of cuts around openings. Keeping one unopened box spare is standard practice for future repairs. The shape of the room matters as much as its size. An L-shaped floor or a room with a chimney breast has more edges, and every edge means a cut. Measuring the room as a single rectangle and adding the alcoves is a serviceable method, but for complicated plans it pays to break the floor into rectangles, add them up, and then add waste on the total. This calculator takes length and width, applies the coverage printed on the box, adds waste and rounds up to whole boxes. It assumes the subfloor is level and ready and does not account for underlay, beading or thresholds. Use it for the flooring order, then add those extras to your list.

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.