Start with net area
Measure the tiled surface and calculate its area before adding waste. Do not apply a waste percentage separately to every small section; add the sections first.
Match waste to complexity
Simple straight layouts often need less extra material than diagonal patterns, many corners or patterned matching. Fragile tiles and batches with wide variation may also justify a larger allowance.
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
- Keep spare tiles from the same batch for later repairs.
- Confirm whether the supplier accepts unopened box returns.