3 x 3 m slab at 10 cm
Concrete needed, with a 7 percent waste allowance, rounded up.
In imperial, that is about 9.8 × 9.8 ft at 3.9 in, roughly 1.26 cubic yards of concrete.
Open the interactive Concrete CalculatorAbout this slab
A 3 by 3 metre slab at 10 cm is 0.9 cubic metres before waste. We add 7 percent for spillage and uneven subgrade and round up to whole bags. A 25 kg bag yields roughly 0.0117 cubic metres and a 20 kg bag about 0.0094.
Confirm the order with your supplier. Uneven subgrade, over excavation and thickened edges all add volume.
Mixing more than a few bags? A heavy duty mixing tub keeps the batch consistent and saves your back. For larger pours, price up ready mix delivery instead.