Fluid Power

Pneumatic Cylinder Sizing

Determine cylinder bore size based on required force and pressure.

Input Parameters

Units:

Calculation Mode

Bore Diameter

Rod Diameter

Supply Pressure

psi

Stroke Length

Cycles per Minute (optional)

cycles/min

Results

Enter cylinder parameters and click Calculate

What is a Pneumatic Cylinder Calculator?

A pneumatic cylinder calculator determines the force output, air consumption, and proper sizing for air-powered linear actuators based on pressure, bore size, and stroke length.

These calculations are essential for selecting cylinders that provide adequate force with safety margin while minimizing air consumption and system costs.

How to Use

Select calculation mode: Force from Size or Size from Force
Enter cylinder bore and rod diameters (or required force)
Enter supply pressure and stroke length
Optionally enter cycles per minute for air consumption
Click Calculate to see force and air requirements

FAQs

During retraction, the piston rod occupies part of the piston area, reducing the effective area that air pressure acts on. This 'annular area' equals the piston area minus the rod cross-section, resulting in 10-30% less retract force depending on rod size.

Seal friction typically reduces actual force to 80-90% of theoretical. For critical applications, multiply calculated force by 0.85 for planning. Friction varies with seal type, age, lubrication, and operating conditions. Break-in period may show higher friction initially.

SCFM (Standard Cubic Feet per Minute) is air flow at standard conditions (14.7 psi, 68°F). CFM is actual volumetric flow at operating pressure. SCFM is used to size compressors since it accounts for the higher density of compressed air.

Rod diameter affects retract force and buckling resistance. Standard rods are typically 1/3 to 1/2 of bore diameter. Use larger rods for push loads (column strength) or when equal extend/retract force is needed (double rod cylinders).

Use the minimum expected supply pressure, not maximum. System pressure drops under load, so design for 80-90% of supply. Typical plant air is 80-100 psi (5.5-7 bar). Higher pressure allows smaller cylinders but increases air consumption and component wear.

Limitations

• Forces are theoretical maximums - actual is 80-90% due to friction
• Does not account for line losses or flow restrictions
• Air consumption varies with supply pressure fluctuations
• Does not check rod buckling for long stroke/high load
• Speed calculations require flow coefficient (Cv) data