How much flooring do I need? Working out m², waste and packs

Buying flooring is a rounding problem: rooms are measured in square metres, but flooring is sold in packs, and every cut you make produces offcuts that may or may not be reusable. Buy too little and you risk a shade mismatch when you reorder a batch weeks later; buy too much and you have paid for boards that end up in the garage. This guide walks through the three steps: measuring the room, choosing a waste percentage, and converting to packs.

Step 1: Measure the room area

For a simple rectangular room, multiply the longest length by the widest width, measuring in metres at floor level (skirting boards can make walls look straighter than they are).

For anything more complicated, split the floor into rectangles and add them up:

• L-shaped rooms: two rectangles.
• Alcoves and bay windows: measure each recess separately and add it.
• Chimney breasts and fixed units: you can subtract these, but for small obstacles it is safer not to, because the "extra" area quietly pads your waste allowance.

Measure each dimension twice, at both ends of the wall. Old walls are rarely parallel, and the difference tells you whether you will need tapered cuts along one side.

A room of 5.2 m × 3.5 m gives 18.2 m².

Step 2: Add waste, and let the pattern decide how much

The single biggest mistake is using one fixed "add 10%" rule for every job. The right allowance depends mostly on your laying pattern and room shape:

Why the spread? In a straight lay, the offcut from the end of one row can usually start the next row, so very little material is truly lost. Diagonal and herringbone layouts produce triangular offcuts at every wall, and far fewer of them are reusable.

Room proportions matter too. If your room width is an awkward multiple of the board width, the last row becomes a thin rip cut and the offcut from it is waste. This is exactly the kind of thing a layout planner catches before you buy: it simulates the actual board placements and counts real offcuts, rather than guessing with a flat percentage.

For our 18.2 m² room with a straight lay and one alcove, use 10%: 18.2 × 1.10 = 20.0 m² to buy.

Step 3: Convert square metres to packs

Every pack states its coverage, typically somewhere between 1.5 m² and 2.6 m² depending on board size. Divide and round up:

• Required area: 20.0 m²
• Pack coverage: 2.22 m²
• 20.0 ÷ 2.22 = 9.01 → 10 packs

Rounding up matters even when the division looks clean: a single damaged or badly bowed board (not rare in budget laminate) eats your margin instantly.

Batch numbers: the reason not to under-buy

Flooring is produced in dye batches, and two batches of the "same" product can differ visibly in shade. If you run short and the shop's current stock is a new batch, the mismatch will be in the middle of your floor. When you buy, check the batch number printed on each pack is the same, and if you are on the fence between 9 and 10 packs, buy 10 and keep the receipt.

Skip the estimating: plan the actual layout

Percentages are guesses. The exact answer comes from placing every board: which rows need cutting, which offcuts can be reused, and how many full boards the layout really consumes. Floor Optimizer does this in your browser: draw the room (alcoves, angles and all), enter your board size, and it returns the exact board count and a cut list, so the number of packs is arithmetic instead of a rule of thumb.