This metric room uses separate repeated wall rows and a ceiling. Exact millimetre sheet dimensions are normalized against metre project dimensions before whole-sheet rounding.
1. Gross area is 45.6 m²
Two 4 × 2.4 m walls contribute 19.2 m². Two 3 × 2.4 m walls contribute 14.4 m². The 4 × 3 m ceiling contributes 12 m². Add the visible rows: 19.2 + 14.4 + 12 = 45.6 m². Door and window openings are not subtracted because this example has no sheet placement or offcut reuse plan.
2. Explicit 8% makes 49.248 m²
The user enters the whole number 8. Purchase area equals 45.6 × 108 ÷ 100 = 49.248 m². This step is exact because 45.6 is parsed from decimal text as a rational value. The displayed calculator may show a rounded area for reading, while the sheet division continues with the exact fraction. A different user-selected waste percentage changes this result without altering measured surfaces.
3. Exact metric sheets round to 18
A 1200 × 2400 mm sheet has 1,200 mm × 2,400 mm = 2,880,000 mm², equal to 2.88 m². Divide 49.248 m² by 2.88 m² to obtain exactly 17.1. The whole-sheet estimate uses ceiling and becomes 18. The service does not replace this preset with 4 × 8 ft or assume the two products have equal face area.
4. Optional cost is 212.40
At an entered price of €11.80 per selected sheet, cost equals 18 × €11.80 = €212.40. The calculator retains the decimal price exactly and formats the final product to two decimal places. It does not include taxes, delivery, labour or finishing materials. The number is useful only when the price belongs to the same 1200 × 2400 mm sheet used in the area calculation.