How to calculate how much concrete you need

Calculate how much concrete need is a fairly basic process, and the same methods to calculate both work surface and concrete walls are used. The formula for calculating any cubic measurement is to multiply the length by width by height then. The general rule when calculating concrete requirements is always rounded up, you better have an excess if not having enough.


  1. It measures three dimensions of the wall or block. Measure the two longest dimensions by increments of one foot (0.3 m), rounded up if necessary. It measures the smallest dimension (the thickness of the wall or block) in inches whole (one inch 2.5 cm).
  2. Multiplies the long dimensions in feet by the thickness in inches and divided by 2 to determine your particular requirements in cubic feet. For example, a concrete wall 16 feet high, 9 and 8 thick high (4.8 2.7 2.4 cm) is 16 by 9 by 8 divided by 12 which is equal to 96 cubic feet (16 x 9 x 8/12 = 96 cubic feet [2.7 m³]).
  3. Changes cubic feet to cubic yards or lots of bags, there are 27 cubic feet (0.7 cubic meters) per cubic yard, so for the previous 96 cubic feet by dividing by 27 example 3.56 cubic yards (2.7 cubic meters) is obtained. In this case, batch commands 4 yards (3.6 m). (It is common to omit the “cube”). To know the number of bags, divide the number of cubic feet or 0.67 2/3 Following the example, 96 cubic feet require 144 bags (96 / 0.67 = 143.3).

Tips & Warnings

  • Although not necessary, a calculator for construction using inputs feet and inches, it makes easier the concrete calculations.
  • Check twice your measurements and your specific calculations before buying.