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Concrete Bags Needed Calculator

How many premix bags to fill a slab or footing.

Compute how many bags of pre-mixed concrete are needed to fill a slab, footing, or column of given length, width, and depth, based on the per-bag yield (typically 0.6 ft³ for an 80-lb bag).

Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

in
in
in

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Volume_ft³ = L · W · D / 1728. Bags = ceil(volume / yield_per_bag).

In depth

Compute how many bags of pre-mixed concrete are needed to fill a slab, footing, or column of given length, width, and depth, based on the per-bag yield (typically 0.6 ft³ for an 80-lb bag).