Flooring Calculator
See exactly how many boxes of flooring to buy for your room — floor area and waste allowance included.
Always rounds up
You can only buy whole boxes, so the result is rounded up to the next whole box — never short on the day.
Add a waste allowance
Cuts, breakages, and future repairs eat into your stack — 10% extra is the usual rule of thumb.
How much flooring do I need?
Room size, box coverage, and a little extra
The amount of flooring you need comes down to three things: the area of your room, how much one box covers, and how much spare you keep for cuts and breakages. Multiply the room length by its width for the floor area, add a waste allowance, then divide by the coverage of a single box and round up to whole boxes. Enter your figures above to see both the floor area and the number of boxes to buy.
Enter your room length and width, the coverage per box, and your waste allowance to get the number of boxes to buy.
First work out the floor area — length times width. Multiply by one plus the waste percentage to cover offcuts, then divide by the area one box covers and round up to whole boxes.
Boxes = ⌈area × (1 + waste%) ÷ coverage per box⌉A 5 m × 4 m room is 20 m². Add the 10% waste allowance to get 22 m² of flooring to buy; divide by the 2 m² each box covers and you get 11 — so you need 11 boxes.
Suppose you are flooring a 5 m × 4 m room with boxes that cover 2 m² each and a 10% waste allowance.
Find the floor area
5 m × 4 m = 20 m² of floor to cover.
Add the waste allowance
20 × 1.10 = 22 m² of flooring to buy.
Divide by box coverage and round up
22 ÷ 2 = 11, rounded up to 11 boxes to buy.
The figure is the number of whole boxes to buy, so always round up — a part box still means purchasing a full one. Laminate, vinyl, and hardwood are all sold by the box, with the coverage in m² printed on the label, so check that figure against the value you entered. The standard 10% waste allowance covers ordinary cuts and the odd breakage on a straight layout; bump it up to 15% for diagonal or herringbone patterns, where each cut leaves a larger offcut, and for rooms with many corners and obstacles. Keep a few spare planks from the same batch, since colour and finish vary between production runs.
The arithmetic is exact, but a real room adds a few wrinkles.
Layout, pattern, and batch matching
The calculator assumes a simple rectangular room and ignores the plank layout and pattern — L-shaped rooms, alcoves, and diagonal or herringbone designs generate more offcuts, so measure each section separately and lean towards the higher end of the waste range. Always buy from the same batch in one go, since dye lots vary between production runs and a later top-up may not match.