The volume of a 50kg bag of cement in liters varies depending on its density, which can vary slightly depending on factors such as composition and manufacturer. However, as a rough estimate, a bag of 50kg cement usually contains about 0.035 cubic meters or 35 liters of cement.

In general, a 50kg bag of cement is about 35 liters, while a 40kg bag of cement is about 28 liters. Likewise, a 25kg bag of cement is about 17.5 liters, while a 20kg bag of cement is about 14 liters. In addition, a 30kg bag of cement is about 21 liters.

The density or unit mass of cement is about 1440 kilograms per cubic meter (kg/m3), which means one cubic meter of cement weighs about 1440 kg, and 1m3 or 1,440kg of cement is equivalent to 1000 liters.

To calculate the volume of cement in liters, first divide the cement weight by its density to find the cubic meters of cement, then multiply the cement volume in m3 by 1000 to get the volume in liters. For example, the volume of a 50 kg bag of cement in liters = (50/1440) × 1000 = 34.72, or rounded to 35 liters.

For a 1 kg cement to liters, the volume can be derived as follows: as 1440 kg cement = 1 m3, so 1 kg cement = 1/1440 m3 = 0.000694 m3, as 1 m3 = 1000 Liters, which means 1 kg of Cement = 0.000694 x 1000 Liters = 0.694 Liters. Therefore 1 kilo or 1 kg of cement would be approximately 0.694 Liters.

**Here’s are general estimates for how many litres is a 50kg, 40kg, 25kg and 20kg bag of cement:**

- There are approximately 35 liters in a 50kg bag of cement. The volume of a 50 kg bag of cement in liters = (50/1440) × 1000 = 34.72, or rounded to 35 liters. Therefore, a 50kg bag of cement typically contains about 35 liters of cement.
- There are approximately 28 liters in a 40kg bag of cement. The volume of a 40 kg bag of cement in liters = (40/1440) × 1000 = 27.77, or rounded to 28 liters. Therefore, a 40kg bag of cement typically contains about 28 liters of cement.
- There are approximately 21 liters in a 30kg bag of cement. The volume of a 30 kg bag of cement in liters = (30/1440) × 1000 = 20.83, or rounded to 21 liters. Therefore, a 30kg bag of cement typically contains about 21 liters of cement.
- There are approximately 17.5 liters in a 25kg bag of cement. The volume of a 25 kg bag of cement in liters = (25/1440) × 1000 = 17.36, or rounded to 17.5 liters. Therefore, a 25kg bag of cement typically contains about 17.5 liters of cement.
- There are approximately 14 liters in a 20kg bag of cement. The volume of a 20 kg bag of cement in liters = (20/1440) × 1000 = 13.88, or rounded to 14 liters. Therefore, a 20kg bag of cement typically contains about 14 liters of cement.

**Conclusions**:

In general, a 50kg bag of cement is about 35 liters, a 40kg bag is about 28 liters, a 25kg bag is about 17.5 liters, a 30kg bag is about 21 liters, and a 20kg bag is about 14 liters.