Where the waste goes
Flooring is cut at every wall, doorway and obstacle. The offcut from the end of one row can sometimes start the next row, but not always, and some pieces arrive damaged or get miscut. A simple rectangle laid in straight rows loses the least; diagonal and herringbone layouts, patterned products that need matching, and rooms with many corners lose more.
Flooring makers sometimes state an allowance for their product in the installation instructions. Our calculator never adds one you didn’t choose.
Measuring an awkward room
- Split the room into rectangles that don’t overlap, or use the L-shape option for one missing corner.
- Add closets and alcoves you’ll floor as extra areas; leave out islands, hearths and built-ins.
- Measure into door openings as far as the transition will sit.
- Measure each wall twice, at opposite ends. Rooms are rarely perfectly square, so use the longer figure.
Worked example
An L-shaped room 20 × 15 ft with an 8 × 6 ft corner missing is 252 sq ft. Leave out a 3 × 4 ft closet you aren’t flooring: 240 sq ft. With 5% waste: 252 sq ft. At 23.4 sq ft per box: 10.77, so 11 boxes.
Rounding and spares
Always round up to whole boxes. Check that the lot numbers on the boxes match, since colour can vary between batches, and keep any unopened leftover box for future repairs.
Roll goods are different
Sheet vinyl and carpet come in fixed widths, so waste depends on how many strips fit across the room and which way they run, not on a percentage. A 12 × 15 ft room in a 12 ft wide roll needs one 15 ft strip running one way, but two 12 ft strips running the other.