Estimate how much flooring to buy — total square footage plus number of boxes — from your room size, with waste.
buy = area × (1 + waste); boxes = buy ÷ box_coverage
Add a waste factor to the room area, then divide by the coverage printed on each box.
NWFA recommends 10–15% for hardwood; more for diagonal or feature layouts and natural-variation materials.
A 15 x 20 ft room is 300 square feet. Hardwood and laminate carry about 10% waste for cuts and board culling, so you'd buy about 330 square feet. If each box covers 20 square feet, that's 17 boxes.
For a diagonal install or a room with many jogs and closets, go to 15% waste. Always open and inspect boxes before installing, and rack boards from several boxes at once so any color variation blends across the floor rather than pooling in one area.
Flooring waste factors follow NWFA guidance. Buy from one dye lot to avoid shade differences mid-project.
Flooring is sold by the carton, not the loose square foot, so your real order is always rounded up to whole boxes. Check the coverage printed on the carton — commonly 18–24 sq ft for laminate and engineered wood, 10–15 sq ft for many luxury-vinyl planks. Divide your waste-adjusted area by that figure and round up. The leftover from rounding becomes your attic stock.
Manufacturing batches (called dye lots or run numbers) vary slightly in shade and gloss. Order the whole job from one lot, and keep one full sealed carton in reserve — a future repair pulled from a different lot will read as a visible patch under the same light.
About 10% for a straight layout, 15% for diagonal or patterned installs.
Divide your total area plus waste by the square feet each carton covers, then round up. For example, 200 sq ft at 8% waste is 216 sq ft; at 20 sq ft per box that is 10.8, so you order 11 boxes.
Only very large fixed obstructions. Small ones leave offcuts that cannot be reused, so the waste factor is meant to absorb them rather than deducting their footprint.
Most floating floors need underlayment unless it is pre-attached to the plank, and over concrete you also need a moisture barrier. It is sold by the roll; divide floor area by roll coverage and round up.