Boxes, cutting allowance and repair reserve
Divide measured area plus your chosen cutting allowance by coverage per box, round up to whole boxes, then add any repair-reserve boxes. Material priced by area uses purchased coverage; installation priced by area uses measured coverage. For 200 sq ft, 10% cutting allowance, 22.5 sq ft per box and one repair box, the result is 11 boxes covering 247.5 sq ft.
Before ordering
Measure non-overlapping rectangles in the same unit. Use your exact product label. Confirm subfloor, moisture limits, underlay, pattern, transitions, stock and returns; an eventual refund does not lower your initial budget. Have suspect old materials assessed before removal. TORLYS installation guidance and a manufacturer product specification illustrate why product-specific coverage matters.