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Sonotube and Column Calculator

Concrete for a round column or post hole, which is what a Sonotube form holds: volume from the tube diameter and the depth it is set to.

With hole diameter 1 ft, height 4 ft, waste allowance 10 percent, price per cubic yard 145 usd, concrete comes to 0.13 cu yd — concrete needed. It is reached in 7 steps, the last of which is cubic_ft_waste / 27, and each one is printed on the page with its numbers filled in. The formula is the one published by American Concrete Institute, not an approximation fitted to it.

Formula and sources checked · How we check

diameterheight
What to measure
Concrete needed
0.13 cu yd
0.1 cubic metres
Volume
3.142 cu ft
Volume with waste
cubic_ft * (1 + waste / 100)3.456 cu ft
Concrete needed
cubic_ft_waste / 270.128 cu yd
60 lb bags (0.45 cu ft each)
ceil(cubic_ft_waste / 0.45)8 bags
80 lb bags (0.60 cu ft each)
ceil(cubic_ft_waste / 0.60)6 bags
Weight of the pour
cubic_yards * 4050518.363 lbs
Ready-mix cost at that price
cubic_yards * price18.559

The formula

  1. Volumeshape_slab * (length * width * thickness / 12) + shape_circle * (pi * pow(diameter / 2, 2) * thickness / 12) + shape_footing * (footing_length * footing_width * depth / 12) + shape_column * (pi * pow(hole_diameter / 2, 2) * height) + shape_wall * (wall_length * wall_height * wall_thickness / 12) + shape_stairs * (stair_width * rise / 12 * run / 12 * steps_count * (steps_count + 1) / 2)
  2. Volume with wastecubic_ft * (1 + waste / 100)
  3. Concrete neededcubic_ft_waste / 27
  4. 60 lb bags (0.45 cu ft each)ceil(cubic_ft_waste / 0.45)
  5. 80 lb bags (0.60 cu ft each)ceil(cubic_ft_waste / 0.60)
  6. Weight of the pourcubic_yards * 4050
  7. Ready-mix cost at that pricecubic_yards * price

Formula from American Concrete Institute, Portland Cement Association.

The same calculator, other cases

  • Concrete Slab CalculatorCubic yards and bag count for a rectangular slab, from its length, width and thickness, with the waste allowance kept separate.
  • Concrete Footing CalculatorConcrete for a strip footing or trench, where the run is long and the section small — the shape where a per-yard rounding error costs the most.
  • Concrete Stairs CalculatorConcrete for a flight of steps, treated as stacked rectangles rather than a wedge, because that is how the forms are actually built.
  • Concrete Wall CalculatorConcrete for a poured wall from its length, height and thickness, with the same waste allowance the slab calculation uses.

Undecided? The Concrete Calculator carries every case behind one control.

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