In order to calculate the volume of any cement bag,
We need to know the density of cement bag.
The unit weight of the bag is 50 kgs
Density of cement in loose condition is 1440 kgs/m3
Density = mass/volume (ρ=m/V)
50 kg ÷ 1440 kg/m3 = 0.0347 m3 = 1.23 CFT
A step by step explanation in this video
Credits on this video: SL Khan