Calculate hydraulic cylinder force, speed, and power from pressure, bore, rod, and flow rate. Supports extend and retract calculations.
Hydraulic systems transmit force through pressurized fluid using Pascal's law: pressure applied anywhere in a confined fluid is transmitted equally in all directions. A hydraulic cylinder converts this fluid pressure into linear mechanical force, with the force equal to pressure times piston area (F = P × A).
This calculator analyzes single-acting and double-acting hydraulic cylinders. You enter the system pressure (or required force), bore and rod diameters, and flow rate. The tool computes extend and retract forces, piston speeds in both directions, area ratios, and the hydraulic power required. Because the rod occupies part of the piston area on the retract side, retract force is always less than extend force — but retract speed is faster at the same flow rate.
Cylinder size presets cover typical ranges from compact 25 mm bore actuators up to heavy-duty 200 mm bore cylinders used in presses and construction equipment. The pressure–force table shows output at standard system pressures.
Use this calculator when you need to connect cylinder geometry, pressure, and flow to the real outputs of a hydraulic actuator.
It is useful for sizing cylinders, checking whether a pump can deliver the required speed, and comparing extend versus retract performance before hardware is selected. That makes it a practical screening tool when force, stroke speed, and pump capacity all have to work together in the same design.
Force (extend): F = P × A_bore = P × π/4 × D² Force (retract): F = P × A_annulus = P × π/4 × (D² − d²) Speed: v = Q / A Power: P_hyd = ΔP × Q Where: • P = system pressure (Pa) • D = bore diameter (m), d = rod diameter (m) • Q = volumetric flow rate (m³/s)
Result: Extend force ≈ 19.6 kN, Retract force ≈ 13.5 kN
A_bore = π/4 × 0.05² = 1 963 mm². F_ext = 100×10⁵ × 1.963×10⁻³ = 19 635 N ≈ 19.6 kN. The annulus area (minus rod) gives lower retract force.
Hydraulic cylinder calculations are most useful when force, speed, and power are viewed together. A cylinder that can make the target force may still move too slowly at the available flow, and a cylinder sized for speed may demand more pump power than the system can deliver continuously.
The most common errors are mixing bore area with annulus area, forgetting the relief-valve limit, and sizing directly to the theoretical force with no safety margin. Real cylinders also lose some performance to friction, seal drag, and pressure losses in hoses and valves, so treat the ideal calculation as the starting point, not the guaranteed output.
On the retract side, the rod occupies part of the piston area, reducing the effective area from π/4 D² to π/4 (D²−d²). Less area means less force at the same pressure.
The annulus area is smaller, so the same flow rate fills the smaller volume faster: v = Q/A. This is the speed–force trade-off in differential cylinders.
Mobile equipment often runs at 200–350 bar. Industrial presses may reach 700 bar. Standard component ratings are typically 160, 210, 250, or 315 bar.
Determine the required force, divide by the maximum system pressure, and solve for bore diameter: D = √(4F / πP). Then choose the next standard bore size up.
When the rod diameter is roughly 0.707 × bore diameter, the annulus area is exactly half the bore area. This gives a 2:1 extend-to-retract force ratio and is common in regenerative circuits.
Higher temperatures reduce oil viscosity (better flow, less pressure loss) but also reduce seal life and lubricant film strength. Most systems target 40–60°C operating temperature.