Concrete Wall Calculator
Concrete for a poured wall from its length, height and thickness, using the same waste allowance the slab calculation uses and showing it as its own step.
A wall is the pour where the thickness figure is small and the multiplier large: an inch of extra thickness across 30 ft of 8 ft wall is nearly a cubic yard. Enter the finished thickness, not the form spacing, if the forms are sprung.
With wall length 20 ft, wall height 8 ft, wall thickness 8 inch, waste allowance 10 percent and 1 more field, concrete comes to 4.35 cu yd — concrete needed. It is reached in 8 steps, the last of which is 117.33333 / 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
- Volume
106.667 cu ft- Volume with waste
106.66667 * (1 + 10 / 100)117.333 cu ft- Concrete needed
117.33333 / 274.346 cu yd- Cubic meters
4.345679 * 0.76455493.323 m3- 60 lb bags (0.45 cu ft each)
ceil(117.33333 / 0.45)261 bags- 80 lb bags (0.60 cu ft each)
ceil(117.33333 / 0.6)196 bags- Weight of the pour
4.345679 * 405017,600 lbs- Ready-mix cost at that price
4.345679 * 145630.123
Several at once
A job is rarely one of anything. Work out the first, add it, change the figures and add the next — the list keeps what each line was, and totals them.
Does the reinforcing displace concrete?
Not by enough to subtract. Rebar in a typical wall takes up well under one per cent of the volume, which is inside the rounding you already do when ordering. Openings are the real deduction: a 3 by 7 ft doorway in an 8 in wall is 1.4 cubic feet you would be paying for and not pouring.
How much can you pour at once?
Four feet a lift is the usual limit for a hand-vibrated wall, with the next lift going in before the last has stiffened. That does not change the volume, but it changes the delivery: one truck on site for the whole wall rather than two arrivals an hour apart with a cold joint between them.
The formula
- Volume
shape_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) - Volume with waste
cubic_ft * (1 + waste / 100) - Concrete needed
cubic_ft_waste / 27 - Cubic meters
cubic_yards * 0.764554857984 - 60 lb bags (0.45 cu ft each)
ceil(cubic_ft_waste / 0.45) - 80 lb bags (0.60 cu ft each)
ceil(cubic_ft_waste / 0.60) - Weight of the pour
cubic_yards * 4050 - Ready-mix cost at that price
cubic_yards * price
Formula from American Concrete Institute, Portland Cement Association.
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