- Home
- Calculator
Concrete calculator
Slabs, footings, sonotubes and walls. Get cubic metres, a truck load plan, and the short-load fee you skip with volumetric.
1 · Project type
2 · Waste & mix
5%
5% for prepared subgrade · 10% for rough subgradeTypical uses — confirm the spec with your designer or building permit.
You need0.00 m³
Order How it works
The math, in the open.
- SlabL × W × T
- FootingL × W × D × qty
- Columnπ × (Ø/2)² × H × qty
- WallL × H × T
- Totalvolume × (1 + waste)
- Loads⌈ total ÷ 8 m³ ⌉
- Free unload15 min/m³, max 90
FAQ
Concrete volume questions.
How do I calculate concrete for a slab?
Multiply length × width × thickness in metres to get cubic metres. A 6 × 4 m slab at 0.15 m (150 mm) is 3.6 m³. Add 5–10% for waste: order about 3.78 m³.
How much concrete for a 20 × 20 ft slab?
At 4 inches: 133 ft³ = 4.94 yd³ = 3.78 m³. With 5% waste, about 3.97 m³.
How do I calculate concrete for sonotubes?
π × (diameter ÷ 2)² × height × quantity. Ten 10-inch (0.254 m) tubes at 1.2 m deep need about 0.61 m³ before waste.
How much waste should I add?
5% for a well-prepared, level subgrade. 10% for rough or uneven subgrade, or forms that may bulge.
What's a partial load?
Any amount less than a full truck. Drum-mixer suppliers usually add a short-load fee. Our volumetric trucks mix on site, so you pay only for the concrete you pour.
Should I use metric or imperial?
Either. The calculator converts both ways. We dispatch in cubic metres (1 yd³ = 0.765 m³).