Concrete Calculator

x x =



Below is the formula for Concrete calculation formula

Calculate the slab volume

Slab Volume = Length x Width x Height / Thickness

Calculate the number of bags

Number of bags = Density of the concrete * Volume of the slab / Weight bag
The loss is then calculated by adding the defined% to the total.


The weight of concrete

Below in the table you can find different types of concrete as well as the density or weight per cubic meter(m3).

Concrete weight depends on the density of the materials and the amount of air it contains.

Type of concrete Metric density Imperial Density
Mix bag 2130 kg / m3 (2110 kg / m3 to 2150 kg / m3) 133 lbs / ft3 (130 lbs / ft3 to 135 lbs / ft3)
For structure 2300 kg / m3 (2240 ??kg / m3 to 2400 kg / m3)
Reinforced concrete (ex slab or counter) 2400 kg / m3 (2300 kg / m3 to 2500 kg / m3)

It has been found that concrete mixes require about 1L per +/- 13 kilogram of concrete mix.

Concrete preparation

When we prepare concrete, we need to mix materials like cement, sand, gravel and water together. It has also been observed that in some cases when we add metal or plastic to it, then concrete’s strength may increase. As an example you can take reinforced concrete.

Concrete dosages

Dosages are not specifically defined for all types of work. However, volume approximations give this:

Type of construction

  • Foundation or terrace
  • Cement: – 1
  • Sand: – 5 (2.25 to 2.75)
  • Gravel: – 5 (3.25 to 3.75)
  • Water: – 5 (0.4 to 0.6)
  • Concrete for post setting
  • Cement:- 1
  • Sand:- 2 (1.75 to 2.25)
  • Gravel:- 3 (2.75 to 3.25)
  • Water:- 0.5 (0.4 to 0.6)

You can simply measure the dosages in concrete by following method:

1 serving of cement, 2 servings of sand, 3 servings of gravel and 1/2 of water

Concrete in kg

Type of construction

Concrete for foundation or terrace

Cement:- 350kg

Sand:- 825kg (800kg to 850kg)

Gravel:- 1200kg (1150kg to 1250kg)

Water:- 175kg (1kg = liter)

Concrete for post setting

Cement:- 350kg

Sand:- 700kg (675kg to 725kg)

Gravel:- 1050kg (1000kg to 1100kg)

Water:- 175kg (1kg = liter)

Also, it is always better to add extra of 10 to 15 percent to consider the loss during concrete work.

Signup With Newsletter

Keep up to date!

Quarterly newsletter to keep up with changes in calculations / rates and improvements.