Hydraulic cylinder calculator

Enter bore, rod diameter, stroke, pressure and pump flow to get push and pull force, extend and retract speed, oil volume and the pump motor power. The piston rod is checked for Euler buckling for the mounting style, and the minimum bore for a given load is calculated.

What it calculates

• Push and pull force in kN and as lifting capacity in kg
• Extend and retract speed, cycle oil volume, area ratio φ
• Hydraulic and motor power from pressure and flow
• Euler buckling load and safety factor for four mounting cases; ISO 3320 standard bores

Formulas

A1 = π·D²/4      A2 = π·(D² − d²)/4      φ = A1/A2
F_push = p·A1·η    F_pull = p·A2·η    [p bar × 0.1 = N/mm²]
v_out = Q/A1    v_in = Q/A2    V = A·s
P_hyd [kW] = p [bar] · Q [l/min] / 600
Euler: F_k = π²·E·I / (K·L)²,  I = π·d⁴/64,  E = 210 000 N/mm²

Worked example

How to use it

1. Create a free account with Google or e-mail.
2. Open the calculator and enter your values; units can be metric or imperial.
3. Read the result with its formula and source, and export to PDF, DXF or CSV where available.

Frequently asked questions

How do I calculate hydraulic cylinder force?

Force = pressure × piston area. In practical units F [N] = p [bar] × 0.1 × A [mm²]. On the rod side use the annulus area π·(D² − d²)/4.

How do I check the rod for buckling?

Use Euler's formula with the free buckling length K·L for the mounting style and compare with the push force; a safety factor of 3–4 is common.

What pump power do I need?

P [kW] = p [bar] × Q [l/min] / 600, divided by the overall pump efficiency.

Guides

• Hydraulic cylinder force chartThe push force of a hydraulic cylinder is pressure times piston area.

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Results are engineering estimates for planning. They do not replace the applicable standard, a qualified procedure or a check by a qualified engineer.