Flooring Calculator
Work out how many boxes of flooring you need from the room size, the coverage per box and a waste allowance.
How it works
boxes = ceil(length × width × (1 + waste%) ÷ coverage per box)
Multiply length by width for the floor area, add the waste allowance, then divide by the coverage printed on each box and round up — you cannot buy a partial box. Ten percent is the usual allowance for straight plank layouts, covering end cuts, defects and future repairs; diagonal and herringbone patterns need more.
Worked example
A 15 × 12 ft room is 180 sq ft. With 10% waste that is 198 sq ft; at 20 sq ft per box you need 198 ÷ 20 = 9.9, rounded up to 10 boxes.
Frequently asked questions
How much waste should I add?
About 10% for straight-laid planks, 15% for diagonal or herringbone patterns, and up to 20% in rooms with lots of jogs, closets and angles. Keep the leftover full plank or two for future repairs.
Do I subtract for cabinets and islands?
For a rough order, no — the extra covers waste. For a precise take-off, subtract permanent fixtures over about 10 sq ft, but keep the waste percentage on what remains.
Why buy from one dye lot?
Wood stain and tile glaze vary batch to batch. Boxes from a single production run match; a reorder weeks later can be visibly off, especially across a large open floor.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.