Pneumatic Cylinder Calculator
This pneumatic cylinder calculator finds the extend and retract force of an air cylinder from its bore, rod, and supply pressure, and the free air it uses per minute from the stroke and cycle rate. It works for double acting and single acting cylinders and shows force in newtons, pounds force, and kilograms force.
Results
The Pneumatic Cylinder Calculator is part of our Fluids collection. Browse more fluids to size, convert, and check your work alongside this tool.
What the pneumatic cylinder calculator does
An air cylinder pushes with the air pressure acting on the piston area and pulls with the pressure on the smaller ring around the rod. The pneumatic cylinder calculator works out both forces, then the volume of air each cycle uses, converted to free air at atmospheric pressure, the figure compressors are rated in. It also shows a practical force at a 70% load ratio, since friction and the need to move quickly eat into the theoretical value.
Pneumatic force formula
Force is pressure times area; air use counts both chambers for double acting cylinders:
With P in bar and areas in mm², multiply by 0.1 to get newtons. The ratio (P + 1.013) ÷ 1.013 converts compressed volume to free air.
Pneumatic cylinder calculator example
A 50 mm bore, 20 mm rod double acting cylinder at 6 bar, 100 mm stroke, 10 cycles per minute:
Retract force is 990 N. At a 70% load ratio the cylinder can move about 825 N reliably.
How to use the pneumatic cylinder calculator
Enter the bore and rod diameters in millimeters and the supply pressure in bar; 6 bar is a common shop pressure, about 87 psi. Choose double acting or spring return. Add the stroke and cycles per minute to get the air consumption. Press Calculate to read the forces and the air use.
Reading pneumatic cylinder force
The theoretical force assumes static pressure and no friction. For a cylinder that must move at a reasonable speed, size for a load ratio of 50 to 70%, so the cylinder has force to spare for acceleration and seal friction. Air consumption adds up across all cylinders on a machine; add it to blow-offs and tools when sizing the compressor, and allow for leaks.
When to use an air cylinder calculator
- Picking a bore size for a clamp, press, or pusher
- Checking whether shop pressure is enough for a load
- Working out compressor demand for a machine
- Comparing single and double acting cylinders
- Converting between N, lbf, and kgf
Common pneumatic cylinder calculator mistakes
- Using compressor pressure. Use the pressure at the cylinder.
- Sizing at 100% load. Leave margin for friction and speed.
- Ignoring the rod side. Retract force is lower.
- Forgetting free air. Compressors are rated in free air, not compressed volume.
Tips for air cylinder sizing
- Use flow controls on the exhaust side for smooth motion.
- Add cushions for fast strokes with heavy loads.
- Regulate pressure down where full force is not needed.
Pneumatic cylinder sizing step by step
Start with the load and how the cylinder moves it. Lifting needs force equal to the weight, while pushing a load on a surface needs only the friction force, often a fraction of the weight. Divide the required force by your load ratio, say 0.6, then by the lowest pressure the machine will see, not the compressor setting, since pressure drops through hoses, valves, and filters. The result is the area you need; choose the next ISO bore up. Check the retract force too if the cylinder pulls a load back. For very large forces at modest speed, oil does the job better, and the hydraulic force calculator covers that case.
Cylinder air consumption and the compressor
Every cylinder stroke dumps its compressed air to atmosphere, so air use scales with bore squared, stroke, pressure, and cycle rate. A machine with ten cylinders like the example uses about 250 L/min, close to 9 CFM, before leaks. Add all cylinders, blow-off nozzles, and tools, then size the supply with the air compressor size calculator. Lowering the pressure where full force is not needed is one of the quickest ways to cut compressed air costs.
Air cylinder force chart at 6 bar
Theoretical force in newtons for ISO bore and rod sizes:
| Bore / rod (mm) | Extend (N) | Retract (N) |
|---|---|---|
| 16 / 6 | 121 | 104 |
| 20 / 8 | 188 | 158 |
| 25 / 10 | 295 | 247 |
| 32 / 12 | 483 | 415 |
| 40 / 16 | 754 | 633 |
| 50 / 20 | 1,178 | 990 |
| 63 / 20 | 1,870 | 1,682 |
| 80 / 25 | 3,016 | 2,721 |
| 100 / 25 | 4,712 | 4,418 |
Pneumatic Cylinder Calculator FAQ
How do you calculate pneumatic cylinder force?
Multiply the pressure by the piston area. At 6 bar, a 50 mm bore with 1,963.5 mm² gives 0.6 N/mm² × 1,963.5 = 1,178 N.
How much air does a cylinder use?
Take the swept volume of each chamber per cycle, convert to free air with (P + 1.013) ÷ 1.013, and multiply by cycles per minute. The example uses 25 L/min.
Why use only 50 to 70% of the force?
Seal friction, valve and line losses, and the need to accelerate the load mean a cylinder sized at 100% moves slowly or stalls.
How do I convert psi to bar?
Divide psi by 14.5. 90 psi is about 6.2 bar.