Air Cylinder Force and Air Consumption Calculator

Calculate the push and pull force of a pneumatic cylinder from its bore, rod diameter and air pressure, and estimate how much compressed air it uses.

Cylinder (inches and psi)

Bore diameter (in)

Rod diameter (in)

Supply pressure (psig)

Stroke (in, optional)

Cycles per minute (optional)

One cycle is one extend plus one retract. Pressure is gauge pressure (psig). Common bore sizes are 1-1/16, 1-1/2, 2, 2-1/2, 3-1/4 and 4 in.

Theoretical force. Friction, seal drag and back-pressure reduce real output, often by 5-20%. Size the cylinder with margin, and do not use air cylinders as the only means of holding a load where a failure could cause injury.

How it works

Force is pressure times area. On the extend stroke, air acts on the full piston area. On the retract stroke, the rod takes up part of that area, so the pull force is lower. Air use comes from the volume swept each cycle, multiplied by how many atmospheres of pressure the air is compressed to.

extend area = π / 4 × bore²
retract area = π / 4 × (bore² − rod²)
force = pressure × area
free air per cycle = (extend area + retract area) × stroke / 1728 × (psig + 14.7) / 14.7 [ft³]

Worked example

A 2 in bore cylinder with a 0.625 in rod, 6 in stroke, at 80 psig and 10 cycles per minute.

Extend force = 80 × 3.1416 = 251 lbf.
Retract force = 80 × 2.835 = 227 lbf.
Air per cycle = 0.134 ft³ of free air, so 1.34 SCFM at 10 cycles per minute.

Common questions

What size compressor do I need?

Add up the consumption of everything on the air system, include a margin for leaks (often 20-30% in older plants), and size to the total. The calculator gives only one cylinder's consumption.

Why is retract force lower?

The rod occupies part of the piston area on the rod side, so less area is exposed to pressure.

Calculations are provided for convenience and education. Verify results against manufacturer data and apply appropriate safety factors.