Flooring Calculator

Flooring is sold by the box, and box coverage varies from about 16 to 30 sq ft depending on plank size and thickness. So the order is always area × waste factor ÷ coverage per box, rounded up. Because of that rounding, the real surplus usually lands above the waste factor you asked for — which is a feature, since you want spare planks.

That is 180 sq ft. With 10% waste you need 198 sq ft, and at 20 sq ft per box that rounds to 10 boxes covering 200 sq ft. Your true surplus is 20 sq ft, about 11% over the room. Keep a full unopened box if the store allows returns until the job is signed off, and hold back several planks permanently for repairs.

Ten percent covers a straight lay in a simple rectangle. Use 15% for diagonal installations, for very long or narrow rooms where more planks need end cuts, and for patterns like herringbone that consume material at every join. Add more if the flooring has a strong repeat you intend to align, or if the room has bays, angled walls, or lots of doorways.

Buy every box in one order with matching lot numbers — colour and gloss shift between production runs. Run planks parallel to the longest wall or toward the main light source, and stagger end joints by at least 6 inches, never lining them up in a stair pattern. Most wood and laminate needs 48 hours acclimating in the room before installation; skipping it is the usual cause of gaps and buckling later.

Budget underlayment for the full room area unless the planks have it pre-attached, plus a moisture barrier over concrete subfloors. Then there is transition trim at every doorway, quarter-round or new baseboard around the perimeter, and an expansion gap of roughly a quarter inch at every wall — floating floors must never be pinned tight, or they buckle the first humid week.