Flooring is sold by the box, and every box states how many square feet it covers. That makes the ordering maths feel simple: measure the room, divide by the coverage, round up. In practice, the first two steps hide a few traps that cause people to come up one box short on a Saturday afternoon, with the store closed and the dye lot discontinued.
Step 1: measure the floor you will actually cover
Measure the length and width of each room in feet and multiply to get square feet. If the room is not a plain rectangle, split it into rectangles and add them together. An L-shaped living area is two rectangles. A room with a chimney breast or a kitchen island is a rectangle minus the area you will not floor.
Measure to the walls, not to the skirting boards. You will be covering the space under the boards' edges, or the flooring will be trimmed against them, and you want the full area in your total.
Do not forget closets, hallways and the small strip through a doorway if the floor is meant to run continuously. Those small areas add up.
Step 2: add the waste allowance
Every installation wastes some material. Planks are cut at the end of each row, the last row is ripped to width, and a few pieces are always damaged or have flaws. The usual allowances are:
- Straight lay in a simple rectangle: 5 to 7 percent
- Diagonal lay or herringbone: 10 to 15 percent
- Rooms with many corners, alcoves or angles: 10 percent or more
If you are new to installing, lean toward the higher end. Leftover boxes can often be returned unopened, but check the store's policy before you rely on it.
Step 3: divide by box coverage
Suppose the room is 14 ft by 18 ft, which is 252 sq ft. Add 8 percent for waste: 252 × 1.08 = 272 sq ft. If each box covers 20.2 sq ft, then 272 ÷ 20.2 = 13.5 boxes. Boxes cannot be split, so you order 14.
Always round up. Rounding down guarantees a shortage.
Buy from one batch
Manufacturers produce flooring in batches, and colour and grain can shift slightly from one batch to the next. Buy all your boxes at once and check that the batch numbers on the cartons match. If you need extra later, you may not be able to find the same batch.
Keep a spare box
Many installers recommend keeping one or two unopened boxes after the job. If a plank is damaged years later by a dropped pan or a leak, a matching replacement is much easier when you have your own stock.
Underlayment and trim
The flooring is not the only material to count. Underlayment is usually sold in rolls covering a stated area, and it also needs a small waste margin. Baseboard, quarter round, thresholds and transition strips are sold by length, so measure the room's perimeter and door openings separately.
Acclimation
Laminate and engineered wood need to sit in the room for a period (often 48 hours) before installation so they can adjust to temperature and humidity. Plan the delivery date accordingly.
A quick example with two rooms
A bedroom of 12 ft by 13 ft (156 sq ft) and a hallway of 3.5 ft by 11 ft (38.5 sq ft) total 194.5 sq ft. Adding 8 percent gives 210 sq ft. At 24 sq ft per box, that is 8.75 boxes, so order 9. The hallway's narrow shape wastes more material than the bedroom, so a slightly higher allowance is sensible.
Get the total checked
Once you have your room dimensions, a flooring square footage calculator can add rooms together and work out the number of boxes from the coverage printed on the carton. It is a useful second opinion before you place the order.
Summary
Measure the covered area, add a realistic waste allowance, divide by the box coverage, round up, and buy everything from the same batch. Keep a spare box for the future. Those steps take ten minutes and prevent the most common flooring headaches.