Minimum cylinder bore D
mm
— in
Hydraulics · Preliminary sizing
Hydraulic cylinder sizing calculator
Calculate theoretical cylinder bore, an indicative rod diameter and required flow from force, pressure, stroke and target time.
Created v1.0
By Thibaut Grzelak, Mechanical Analysis Engineer
02
Theoretical results
Indicative rod diameter d
mm
— in
Available extension force
kN
— lbf
Available retraction force
kN
— lbf
Required extension flow
L/min
— US gpm
Required retraction flow
L/min
— US gpm
Numerical substitution
—Theoretical values: next choose a larger standard bore and verify rod buckling.
Static preliminary sizing. Back pressure, detailed friction, rod buckling, cushioning, pressure peaks and standard bore series are not checked.
01Calculation method
From force requirement to flow rate
- Calculate required active area with A = F/(Pη).
- Derive D, including d/D for a rod-end calculation.
- Calculate volumes A·L and then flows Q = V/t.
- Select larger standard diameters and repeat the checks.
02Sizing limitations
- Rod buckling must be checked from free length and end conditions.
- Actual force depends on back pressure and friction.
- Pump flow must cover peaks and the complete duty cycle.
- Calculated diameters are not a manufacturer bore series.
Hydraulic preliminary sizing
Size a hydraulic cylinder: force, bore, flow and speed
Pressure and force determine required area. Area sets bore, then flow determines speed and stroke time.
Cap-end bore
Minimum bore depends on required force, available pressure and efficiency.
D = √[4F / (πPη)]Rod-end area
During retraction, the rod reduces active area.
Aa = π(D² − d²) / 4Complete calculation
The dedicated calculator connects force, bore, rod, stroke, time and flow.