Hydraulic cylinder force calculator
This is the ideal force from pressure acting on area — no friction, no seal drag, no back-pressure. Real output is a little lower, and the mounts, pins and structure must carry whatever it produces. Size the system to the rated pressure, not to this ceiling.
Enter the bore, the rod diameter and the working pressure, and the tool gives the push force on the extend stroke and the smaller pull force on retract, in pounds and kilonewtons at once. Force is simply pressure times the area the fluid pushes on.
Worked example
A 3-inch bore is π × 1.5² ≈ 7.07 in² of piston. At 2,000 psi the push is 7.07 × 2,000 ≈ 14,140 lbf, about 62.9 kN. A 1.5-inch rod removes π × 0.75² ≈ 1.77 in², so the pull acts on 5.30 in² — roughly 10,600 lbf.
The formula
push = pressure × (π ÷ 4 × bore²) · pull = pressure × (bore area − rod area)
Force is pressure times area, so the whole job is finding the area the fluid works on: the full piston face on extend, and the piston minus the rod on retract. Keep pressure and area in matching units — psi with square inches, or pascals with square metres.
Questions
- How do I calculate hydraulic cylinder force?
- Multiply the fluid pressure by the piston area. A 3-inch bore has an area of π × 1.5² ≈ 7.07 in²; at 2,000 psi that is 7.07 × 2,000 ≈ 14,140 pounds of push. The tool works out the area from the bore for you and multiplies by the pressure you enter.
- Why is the pulling force less than the pushing force?
- On the retract stroke the rod takes up part of the piston, so the fluid only acts on the ring of area around it. Subtract the rod area from the bore area and multiply by pressure, and you get the smaller pull force. A fat rod means a noticeably weaker pull than push.
- Does this account for friction and efficiency?
- No — it is the ideal, theoretical force from pressure and area alone. Seal drag, back-pressure on the return line and internal losses shave a few percent off in real life. Treat the figure as the ceiling and derate it for the actual system before you rely on it.
- What pressure should I use?
- The working pressure of your system, from the pump setting or the relief-valve set point — it is a field you enter, not a number this tool assumes. Remember that the force scales straight with pressure, so a 10% higher setting is 10% more force, on both the components and the mounts.
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