Linear Actuator Force Calculator

Our linear actuator force calculator computes the maximum force required for the linear actuator.

Extend force1.0053 kN8 bar over 12.566 cm²

Retract force844.4601 N84% of the extend force — the rod takes up part of the piston face

Full bore area12.5664 cm²

Annulus area10.5558 cm²

Extend force in kilograms-force102.51 kgf

Force difference between strokes160.8495 Nwhy a double-acting cylinder is usually mounted to push rather than pull

Swept volume, extending376.99 cm³

Swept volume, retracting316.67 cm³less air or oil needed on the return

Work per extend stroke301.5929 J

Rod speed0.375 m/s

Power while extending376.9911 W

Flow rate needed28.274 litres a minute

At 4 bar502.6548 Nextend force

At 10 bar1.2566 kNextend force

The formula

F = pA, with A = πd²/4

The rod side is weaker

Force is pressure times area, and a double-acting cylinder has two different areas. Extending, the pressure acts on the full bore. Retracting, it acts on the bore minus the rod cross-section, so the force is smaller — often by twenty or thirty percent. That asymmetry is why cylinders are normally arranged so the working stroke is the push.

It also means the return stroke needs less fluid, so a cylinder retracts faster than it extends at the same flow rate. In hydraulics with a fixed pump that produces a noticeably quicker return, which is sometimes useful and sometimes has to be throttled.

Bore enters squared, so a 25% larger bore gives a 56% larger force at the same pressure. Increasing bore is almost always cheaper and safer than raising system pressure, which is limited by seals, hoses and fittings.