Fluid Power

Hydraulic Force Calculator

Determine the force output of a hydraulic cylinder given pressure and piston area.

Input Parameters

Units:

Solve For

System Pressure

psi

Piston Area Input

Bore Diameter

Results

Enter values and click Calculate

What is Hydraulic Force?

Hydraulic force is the output force generated by a hydraulic cylinder when pressurized fluid acts on the piston. Based on Pascal's Law, the force equals pressure multiplied by the piston area (F = P × A).

This simple relationship allows hydraulic systems to multiply force - a small pump can generate enormous forces through large cylinders, making hydraulics ideal for heavy machinery, presses, and lifting equipment.

How to Use

Select your unit system (Imperial or Metric)
Choose what you want to solve for (Force, Pressure, or Area)
Enter the known values
For cylinder area, enter bore diameter or direct area
Click Calculate to get your results

FAQs

Pascal's Law states that pressure applied to a confined fluid is transmitted equally in all directions. This means the pressure at the pump equals the pressure at the cylinder (minus line losses), allowing small pumps to generate enormous forces through large cylinders.

During retraction, the piston rod displaces some of the cylinder volume, reducing the effective area. The annular area (full piston area minus rod area) receives pressure, resulting in less force. For a 4" bore with 2" rod at 3000 psi: extend = 37,700 lbs, retract = 28,270 lbs.

Cylinder seal friction typically reduces output force by 5-10%. For accurate sizing, multiply calculated force by 0.90-0.95 (90-95% efficiency). Higher pressure and larger seals increase friction. Use low-friction seals for precision applications.

Use the pressure at the cylinder port, not pump pressure. Line losses reduce pressure, especially in long runs or undersized hoses. Pressure drops of 50-200 psi are common. Measure actual working pressure at the cylinder for critical applications.

Start with required force plus 25-50% safety factor. Calculate minimum bore at your system pressure. Round up to next standard bore size. Verify the selected cylinder's rated pressure exceeds your system pressure. Consider rod diameter for buckling if pushing loads.

Limitations

• Does not account for seal friction (typically 5-10% loss)
• Assumes pressure at cylinder equals input pressure
• Retract force calculations not included (rod area reduces effective area)
• Does not consider dynamic forces or acceleration
• Always verify cylinder ratings for your application