Hydraulic Power Calculator
Hydraulic Power Calculator
Calculate theoretical hydraulic power from flow and pressure, with an optional efficiency estimate.
Formula: P (kW) = Q (L/min) × p (bar) ÷ 600
Use these results as engineering estimates. Always check the carrier, hydraulic circuit and attachment manufacturer specifications before selecting or operating equipment.
Calculate hydraulic power from flow and pressure
Hydraulic power is a useful way to compare the capability of a carrier’s auxiliary circuit with the demand of an attachment. A machine may provide enough pressure but not enough flow, or enough flow but at a lower pressure. Looking at the combination as power makes those differences easier to understand.
Enter the available flow in L/min and pressure in bar to calculate theoretical hydraulic power. The optional efficiency field gives a simple estimate of how much of that power may remain after system losses.
The hydraulic power formula
For metric values, theoretical hydraulic power is commonly calculated as:
P (kW) = Q (L/min) × p (bar) ÷ 600
For example, 100 L/min at 200 bar represents about 33.3 kW of theoretical hydraulic power. Real usable power will be lower because no hydraulic system is loss-free.
Why efficiency changes the result
Losses occur in the pump, control valves, quick couplers, hoses, fittings and the attachment itself. Oil temperature and viscosity also affect efficiency. The efficiency input in this calculator is therefore a planning estimate, not a substitute for measured system performance.
Where the calculation is useful
Hydraulic power is relevant when comparing breakers, mulchers, augers, compactors, magnets, shears, grabs, rotators and other attachments that rely heavily on the carrier’s auxiliary hydraulics. It can also help explain why two machines with similar pressure ratings perform differently when their available oil flow is not the same.
Use the Flow & Pressure Converter when specifications are provided in GPM or PSI. If the attachment uses a hydraulic motor, continue with the Hydraulic Motor Torque & Speed Calculator.
Frequently asked questions
Is hydraulic power the same as engine power?
No. Engine power is the total mechanical power produced by the engine. Only part of that power may be available to the auxiliary hydraulic circuit.
Why is actual attachment power lower than the theoretical value?
Pressure drop and efficiency losses occur throughout the circuit. Pump condition, valve sizing, hose diameter, oil temperature and motor efficiency all influence the final result.
Can this calculator be used for excavators and loaders?
Yes, provided you use the actual auxiliary flow and pressure available at the circuit intended to operate the attachment.
How to use this calculator
This calculator estimates the hydraulic power represented by a given flow and pressure. It is useful for first-pass checks when comparing carrier auxiliary hydraulics with the requirements of breakers, mulchers, compactors, rotators and other powered attachments.
Typical uses
- Compare a carrier hydraulic circuit with an attachment power requirement.
- Estimate usable output after applying a realistic efficiency factor.
- Check how changes in flow or pressure affect available hydraulic power.
Frequently asked questions
What is the hydraulic power formula?
For common metric units, theoretical power in kW is flow in L/min multiplied by pressure in bar and divided by 600.
Why is usable power lower than theoretical power?
Hydraulic systems lose energy through pumps, valves, hoses, leakage and mechanical inefficiency, so real output is always lower than the theoretical value.
Can I select an attachment using hydraulic power alone?
No. Flow range, maximum pressure, return restrictions, couplers, cooling and the carrier manufacturer limits must also be checked.