A backsplash crossing a corner is easier to audit as separate rows than as one remembered total. This example uses three positive known areas already measured after deliberate decisions about cabinets and openings: 1.80 m², 1.35 m², and 0.75 m². The chosen tile face is 10 × 20 cm, the user-selected extra is 12%, and the exact box label says 25 pieces. The example illustrates aggregation and rounding, not a cut plan.
Add measured panels before dividing by tile area
The three panels total 1.80 + 1.35 + 0.75 = 3.90 m². Each 10 × 20 cm tile has a face area of 200 cm², or 0.02 m². Dividing 3.90 m² by 0.02 m² gives exactly 195 net tiles. Keeping the wall panels as separate rows preserves the source and exposes a duplicated or omitted measurement, even though the arithmetic eventually uses their sum. The known areas must already reflect the user’s decision about sockets, windows, cabinet gaps, and other untiled regions. TileCalc does not detect or subtract those objects itself.
Apply 12% and distinguish box rounding
The exact net requirement of 195 multiplied by 1.12 equals 218.4, which rounds upward to 219 purchase tiles. With 25 pieces per box, 219 ÷ 25 = 8.76, so 9 whole boxes are required. Those boxes contain 225 tiles. The six pieces above 219 result from whole-box packaging, not from changing the selected allowance. Before ordering, confirm that 25 pieces applies to the exact 10 × 20 cm variant and check code, finish, colour, batch, returns, and installer guidance. TileCalc does not know whether offcuts cross a corner or whether a chosen pattern creates additional cuts.