Square footage and boxes of flooring with waste allowance.
Always order more than you measure. A 10% waste factor is standard for straight-lay flooring. Diagonal or herringbone patterns waste 15–20% due to angled cuts. Always buy from the same batch/dye lot — colors vary between lots and you cannot always reorder an exact match.
Keep one or two extra boxes after installation for future repairs. Storing them in climate-controlled conditions preserves the finish for patching damaged boards years later.