What you need to know
- Measure every surface you plan to tile and subtract only openings that genuinely remove material.
- Convert tile dimensions to square metres or use stated box coverage.
- Add waste for cuts, breakage and pattern layout, then round up to full boxes.
Use your own measurements
Use the linked BricoDato resource to check these inputs in your own situation. For tiling, measure the installation area, then use the exact number of pieces or square metres per box.
Calculate the surface area
For each rectangular surface, multiply width by height or length by width. Add the areas together and separate walls from floors if they use different products.
Convert the tile format
A 60 × 60 cm tile covers 0.36 m² before joints. In practice it is often easier to use the manufacturer’s stated box coverage and number of pieces per box.
Choose a waste allowance
Simple straight layouts often need less waste than diagonal patterns, small rooms with many cuts or designs that must be centred. Keep spare tiles from the same batch for future repairs.
Round to full boxes
The calculator should round the purchase up. Do not plan to buy a fraction of a box if the retailer sells only sealed packs.
Turn area and tile size into complete boxes
For tiling, measure the installation area, then use the exact number of pieces or square metres per box. Cutting waste differs between a simple running layout and patterns with many corners or niches.
Example to adapt
A rectangular 2.4 m × 2.5 m wall section covers 6.0 m². With a hypothetical 10% cutting allowance the target becomes 6.6 m². If each box covers 1.20 m², 6.6 ÷ 1.20 = 5.5, so buy 6 complete boxes before deciding on spares.
| Waste assumption | Required coverage | 1.20 m² boxes |
|---|---|---|
| 5% | 6.30 m² | 6 boxes |
| 10% | 6.60 m² | 6 boxes |
| 20% | 7.20 m² | 6 boxes |
Checks before acting
- Measure doors, windows and wall niches separately rather than assuming every wall is a rectangle.
- Check actual box coverage, calibre, shade and batch/lot number.
- Decide layout and cut placement before choosing a waste margin.
- Budget adhesive, grout, edge trims and waterproofing separately.
Final check
Work from the net wall or floor area and then lay out the cuts, avoiding the assumption that all offcuts can be reused. For 7 m² with 10% provisional cutting allowance, the target becomes 7.7 m²: a box covering 1.44 m² implies 5.35 boxes, so six whole boxes before any special pattern requirement. Verify batch, calibre, exact box coverage and the specification for wet or external use.
- Measure every tiled surface.
- Confirm box coverage and tile size.
- Allow more waste for complex layouts.
- Keep spare tiles from the same batch.
Keep a small job sheet
Keep dimensions, cut pattern, tile size, box coverage, batch and grout/trim specifications.
Turn the guide into a decision
Keep a cut diagram and write down the seller's m² per box for the precise tile reference, not another size in the range. For waterproofing or structural substrates, obtain the appropriate system specification; ordering enough tiles alone is not a complete installation plan.