The purchase calculation
Multiply room width by length. Apply the allowance you selected. Divide the result by the square-foot coverage printed on the chosen box and round up to a whole box.
Worked example
A 12 × 10 ft room is 120 sq ft. An illustrative 10% allowance gives 132 sq ft. At 23.64 sq ft per box, six boxes provide 141.84 sq ft. That is 21.84 sq ft above the measured floor, but only 9.84 sq ft above the area with allowance.
Choose the allowance with the product and installer
The tool does not recommend a universal waste percentage. Layout, cut patterns and installation requirements are outside this quantity-only estimate. Do not double-count overlapping rectangles when modeling a room in sections.
Where 23.64 comes from: it is the “Sq. Ft. Per Carton” printed for one real 7 in × 48 in luxury vinyl plank (Shaw Distinction Plus, style 2045V-07066). Other products pack different areas per box, so copy the figure from the box you will buy. That manufacturer’s own calculator adds 15% for installation errors; this tool leaves the allowance to you.
Not sure what to measure? Read how to measure a room for paint, wallpaper and flooring.
What this page decides: the boxes a single rectangle needs, once your allowance is applied and the result is rounded up to whole cartons. What it does not decide: the allowance itself, and it takes one rectangle at a time, so an L-shaped room or a closet plus a hallway has to be measured separately and added on paper before you type the total here. Under every result it says what it leaves out: “Purchase quantity only. Allowance is your input, not an installation recommendation. No layout, subfloor, structural or building-code assessment.”
Floors worked through with this calculator
Three worked examples on the fields above. The first two are the cases this calculator cannot take in one run, because it measures one rectangle at a time.
- An L-shaped room in laminate — split it in two, add the areas on paper, and apply the allowance once: counting the same allowance twice costs a box on all three cartons.
- Closet plus hallway: one order or two? — added and bought once they take 2 to 4 cartons; bought separately, two of six cartons cost an extra box.
- A 12-by-15 living room in vinyl plank — why the same floor takes 4 or 11 cartons from the same manufacturer.