Measure the complete tiled surface first
Record every relevant dimension in the same unit and separate irregular sections. Small measuring errors multiply across an entire project, so check each figure before adding a waste allowance.
Apply one allowance
Multiply total net area by one plus the waste percentage. For example, 12 m² with 10% waste becomes 13.2 m² before converting to boxes.
Turn the result into a buying quantity
Calculations produce a net requirement, while shops sell fixed packs. Round up only at the final buying step, compare pack coverage, and keep unopened tile returnable where the retailer permits it.
Practical checklist
- Round up to whole boxes after adding waste.
- Separate wall and floor products when pack coverage differs.