Hydraulic Pressure & Cylinder Force Calculator

Pressure for a required force, or force at a given pressure — on the piston side and the rod side.

Calculator

kN
mm
mm

Leave empty to see the push stroke only.

%

Allows for seal friction; empty = 100 %.

Example Result

Your result will appear here

The calculated result will appear here after you press Calculate.

About the Hydraulic Pressure & Cylinder Force Calculator

A hydraulic cylinder turns fluid pressure into force: pressure times the area it acts on. On the way out (extension) the oil pushes on the full piston area; on the way back (retraction) it pushes only on the ring around the rod, so the same pressure gives less force and the same force needs more pressure. This calculator works both ways — the pressure needed for a required force, or the force available at a given pressure — and shows push and pull separately, with an optional allowance for seal friction. Enter bore and rod diameters in millimetres or inches; results come in bar, MPa and psi, kN and lbf. The pressure it gives is the minimum to move the load; the relief valve and every component must be rated above it.

How to Use the Hydraulic Pressure & Cylinder Force Calculator

  1. 1

    Choose whether you know the force (to find pressure) or the pressure (to find force).

  2. 2

    Enter the bore diameter and, for the pull stroke, the rod diameter.

  3. 3

    Optionally enter a cylinder efficiency to allow for seal friction.

  4. 4

    Press Calculate: push and pull are shown separately — the pull needs more pressure for the same force.

Hydraulic Pressure & Cylinder Force Calculator Examples

Frequently Asked Questions

How do I calculate hydraulic cylinder force?

Force = pressure × piston area. In metric units 1 bar acting on 1 cm² gives 10 N; a 63 mm piston at 160 bar pushes with about 49.9 kN. For retraction use the annulus area around the rod.

How much pressure do I need for a given force?

Divide the force (plus friction) by the area: 100 kN on an 80 mm piston needs about 199 bar to push — and 291 bar to pull with a 45 mm rod.

Why is the pulling force lower than the pushing force?

The rod takes up part of the piston face, so on the return stroke the oil acts on a smaller ring-shaped area.

What efficiency should I use?

Seals take a few percent of the force; if you do not know the figure for your cylinder, use the manufacturer's data or allow a margin.

How do I convert bar to psi?

Multiply by 14.504. 1 MPa = 10 bar = 145.04 psi.

What pressure rating do my hoses and valves need?

At least the relief-valve setting of the circuit, which is set above the working pressure. If the required pressure is beyond your pump or hose rating, choose a larger bore rather than more pressure.

What is Pascal's law?

Pressure in a confined fluid acts equally in all directions, so a small piston can create a large force on a large one — the basis of hydraulic force multiplication.

By O.E. — Partner, chairman of the board and CEO of a metal products manufacturer for 21 years; the company exports to 45 countries.

Drafted with AI assistance; calculations checked against primary sources and tested with the site's own code. About FlowUtil

Last reviewed

Force, pressure and the two areas

Extending, the oil pushes on the full piston area A = π/4 × D²; retracting, only on the annulus A = π/4 × (D² − d²), because the rod takes up part of the face. The pressure needed for a force is p = F ÷ (A × η), and the force available at a pressure is F = p × A × η, where η allows for seal friction. In metric units 1 bar acting on 1 cm² gives 10 N; 1 MPa = 10 bar = 145.04 psi. The pressure calculated is the minimum to move the load — the relief valve is set above it.

SymbolMeaning
DBore (piston) diameter
dRod diameter
ηCylinder efficiency (seal friction)

A press cylinder, and what a 63 mm cylinder delivers

  1. 1A press needs 100 kN from an 80 mm bore cylinder with a 45 mm rod.

    Push: 100,000 ÷ 5,026.5 mm²; pull: 100,000 ÷ 3,436.1 mm²

    Push 198.9 bar (209.4 bar at 95% efficiency) · pull 291.0 bar

    If the same cylinder must also pull 100 kN, the pull decides the system pressure — 46% higher than the push. Accept a lower pulling force or choose a larger bore.

  2. 263 mm bore, 36 mm rod, 160 bar.

    16 MPa × 3,117 mm²; 16 MPa × 2,099 mm²

    Push 49.9 kN (11,213 lbf) · pull 33.6 kN

  3. 33 in bore cylinder pushing 20,000 lbf.

    20,000 ÷ 7.069 in²

    2,829 psi (195 bar) before friction

Pressure ratings and safety

  • Relief-valve settingEvery component in the circuit — pump, valves, hoses, fittings and the cylinder — must be rated for at least the relief-valve setting.
  • Larger bore, not more pressureIf the required pressure is beyond your pump or hose rating, choose a larger bore.
  • Never work on a pressurised circuitRelease stored pressure, including accumulators, before opening any connection.

Formula basis

  1. Pascal's law, p = F ÷ A; cylinder efficiency is your input. Unit factors from the definitions of the bar (10⁵ Pa) and the pound-force per square inch (6,894.757 Pa).

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