Hydraulic Cylinder Calculator
Calculate hydraulic cylinder force and fluid volume per stroke from bore diameter, system pressure, and stroke length.
How this calculator works
A hydraulic cylinder turns fluid pressure into a pushing force by acting on the piston’s bore area. This calculator takes your bore diameter and system pressure, works out the bore area, and multiplies it by pressure to get the extend force — plus the fluid volume the cylinder uses for a given stroke length.
Formula: Force = pressure × bore area (F = PA), where bore area = π × (bore diameter ÷ 2)². Fluid volume per stroke = bore area × stroke length.
Worked example
A 3-inch bore cylinder at 2,000 psi system pressure, with a 10-inch stroke:
- Bore diameter: 3 in
- Bore area: ≈ 7.069 in²
- Extend force: ≈ 14,137 lb
- Volume per stroke: ≈ 70.69 in³ (≈ 0.306 gal)
Notes
This gives the extend (push) force using the full bore area. Retract (pull) force is lower because the rod itself takes up part of the piston area on that side, so a cylinder always pulls with less force than it pushes at the same pressure.
Cylinder speed depends on pump flow rate divided by this same bore area, so a higher-GPM pump moves the same cylinder faster at a given pressure.
How to use
Enter the cylinder’s bore diameter, your system pressure, and the stroke length. The calculator returns the extend force the cylinder can produce and the fluid volume it needs per stroke, useful for sizing a pump or checking whether a cylinder can handle a given load.
A planning estimate using standard hydraulics formulas. For code-governed drainage or civil design, confirm with a licensed civil engineer.
Frequently asked questions
How do you calculate hydraulic cylinder force?
Force equals system pressure multiplied by the cylinder's bore area, written as F = PA. Bore area comes from the bore diameter using the standard circle area formula. This calculator works out the bore area for you from the diameter you enter, then multiplies it by your system pressure to get the extend force.
Why is retract force lower than extend force?
On the extend stroke, fluid pressure pushes against the full piston face. On the retract stroke, fluid pressure pushes against the piston face minus the area taken up by the rod, since the rod occupies part of that side of the piston. With less area to push against at the same pressure, retract force is always lower than extend force for a given cylinder.
How much fluid does a cylinder use per stroke?
Fluid volume per stroke equals the bore area multiplied by the stroke length — essentially the volume of the cylindrical space the piston sweeps through. This figure matters for sizing a hydraulic pump and reservoir, since the pump needs to supply that volume of fluid every time the cylinder completes a stroke.
What determines how fast a hydraulic cylinder moves?
Cylinder speed depends on pump flow rate divided by the bore area, not on system pressure. A higher-GPM pump pushes more fluid into the cylinder per second, moving the same cylinder faster at a given pressure. Pressure determines how much force the cylinder can produce, while flow rate determines how quickly it moves.
Estimates only. Verify quantities with your supplier before purchasing.