Guide to Calculating the Amount of Water in Compressed Air

Tính toán lượng nước trong khí nén

The presence of water in compressed air is an inevitable result of the air compression process. Depending on ambient conditions (such as temperature and humidity) and compression conditions (compressed air temperature and pressure), the amount of water contained in the compressed air system can vary significantly.

Below, you can refer to methods for calculating the amount of water present in compressed air. The results can be used to size and select equipment such as automatic condensate drains, oil-water separators, and other condensate treatment devices.

Learn more: Why water forms in compressed air and how to prevent it

Compressed Air Water Content Calculator

This tool estimates the amount of water in compressed air and the condensate volume at the receiver / after the compressor and after the air dryer, based on air flow rate and ambient conditions.

Compressor FAD at intake conditions (m³/min).
➜ Flow unit converter (m³/min, l/s, CFM…)

Intake air temperature at the compressor inlet (typically 25–40°C).

Ambient air relative humidity (RH).

System operating pressure (bar g). The tool automatically adds 1 bar to convert to absolute pressure.
➜ Pressure unit converter (bar, Pa, psi…)

Enter 100% if the compressor runs fully loaded continuously. Example: if the compressor runs about 70% of the time on average, enter 70. The water amount will be multiplied by this load factor.

Air temperature after the aftercooler / before the receiver.
Note: If no measured data is available, you may estimate: T₂ ≈ Ambient temperature + 15°C.

Dryer PDP (e.g., +10°C for a refrigerated dryer, -20°C for a desiccant dryer).