Flooring guide
How much flooring waste should I add?
Waste is the material needed for cuts, damaged pieces, layout choices, and future repairs. It is added to the measured area before rounding to whole boxes, so the order stays above what you will actually install.
Start with a visible factor
A simple rectangular room is a useful baseline. Enter the room area, choose an editable allowance, and divide by the coverage printed on the box. Boxes round up because a partial carton is not something you can buy.
Boxes = round up(planning area ÷ box coverage)
What the allowance is really doing
In a 120 sq ft room, a 10% allowance adds 12 sq ft. With 20 sq ft cartons, 132 ÷ 20 = 6.6, so you buy 7 boxes, which is 140 sq ft. The extra 8 sq ft comes from rounding, not from the allowance. The flooring calculator shows both parts separately so you can see which one is driving the order.
When to increase it
- Diagonal layouts and herringbone patterns create more offcuts.
- Irregular rooms need more cuts than one open rectangle.
- Long runs, many doorways, and mixed widths make the layout harder.
- Wide or long planks leave bigger offcuts at the end of each row.
- Planks with visible grading or color variation may be culled.
Manufacturer installation instructions should take priority. Shaw installation material, for example, calls out higher waste factors for more complex layouts rather than treating one percentage as universal.
Keep a little back
A few spare planks from the same production lot make later repairs easier, because later lots can differ slightly in color. That is a reason to keep leftovers, not to inflate the allowance.
Reference: Shaw installation-grade waste guidance