What Is Absorbed Power?
Absorbed power is the actual power drawn at the pump shaft to move fluid through a system. It accounts for the energy required to overcome pressure and flow conditions, adjusted for the specific gravity of the fluid and the mechanical efficiency of the pump. Getting this value right is essential for correct motor selection and long-term system reliability.
Oversized motors and poorly matched pumps can lead to wasted energy, unnecessary cost, and reduced system performance. By calculating absorbed power accurately, you can avoid oversizing, prevent equipment stress, and ensure that your pump and motor are optimally matched to the actual requirements of the application. This is especially valuable in pump and motor sizing, where efficiency and precision are critical.
The calculator is widely used in process and utility engineering environments, where dependable pump selection supports stable operations. It's also a valuable tool in energy audits and system optimisation projects, where understanding true power demand helps reduce electricity consumption. In fluid system design and specification work, it provides a dependable foundation for technical decisions.
Whether you're looking for a pump power calculator to support hydraulic power planning, need a tool for shaft power verification, or want to calculate kW for pumps based on flow and pressure conditions, this absorbed power calculator gives you the clarity you need. It’s especially useful when comparing pump flow vs pressure to determine the best fit for a given task—making it a reliable pump sizing tool for both initial designs and retrofit work.
How It Works
The absorbed power (in kW) is calculated using the formula:
Power = (Flow × Pressure × SG) / (K × Efficiency)
Where:
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Flow is the volumetric rate (m³/h)
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Pressure is in bar
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SG is the specific gravity of the fluid
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K is a unit-specific conversion constant
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Efficiency is given as a decimal (e.g., 80% = 0.8)
This calculator converts your input to all major flow units and applies the correct K-value automatically.
