MetraNestMeasure the area to cover
Measure the length and width of each area, then add the areas without counting intersections twice. For an L-shaped floor, use the dedicated calculator. For several walls, separate areas receiving different products or sizes.
The allowance depends on the layout
A square-metre calculation cannot know where the joints and cuts will fall. Diagonal layouts, many corners and some patterns may require more material. The percentage is therefore a project choice. A detailed tile layout estimates cuts more accurately than a universal percentage.
Count the boxes, then check the reserve
The area stated on the box is the simplest purchasing input. A whole box may add a reserve beyond your initial allowance. Review both quantities: target area and purchased area. The theoretical number of tiles is not a laying plan and does not replace checking the actual size.
Required area = measured area × (1 + allowance ÷ 100). Boxes = required area ÷ area per box, rounded up. Purchased area = boxes × area per box.
From the room to the boxes
An area of 12 m² with a chosen 10% allowance requires 13.2 m². If one box covers 1.44 m², nine boxes provide only 12.96 m². You need ten, or 14.4 m² purchased.
Details to check
- Use the coverage area on the box label.
- Separate products before calculating.
- Note the product reference and batch information in case you need to order more.
Frequently asked questions
Does the calculation include joints?
It estimates material by area. The exact effect of joint width depends on the tile layout, which needs a separate check.
Why not always use the same allowance?
Room shape, tile size and laying pattern change the amount of cutting waste. The percentage should reflect your project.
Method and references · Editorial review: 25 October 2026
The geometric formulas are explained here. For a product, its packaging dimensions and coverage rate remain the reference inputs.