Free Engineering Tool — #143
Pneumatic Cylinder Force & Speed Calculator
Calculate extend/retract force and piston speed for pneumatic cylinders. Enter bore, rod diameter, and supply pressure.
Results
Cylinder Extend Force
When the piston extends, pressure acts on the full bore area:
Cylinder Retract Force
When retracting, the rod occupies part of the piston, reducing effective area:
Piston Speed
Speed depends on the air flow rate and effective piston area:
- P — supply pressure
- D — bore diameter
- d — rod diameter
- Q — volume flow rate at working pressure
Standard Bore Sizes (ISO 15552)
| Bore (mm) | Rod (mm) | Extend Area (cm²) |
|---|---|---|
| 32 | 12 | 8.04 |
| 40 | 16 | 12.57 |
| 50 | 20 | 19.63 |
| 63 | 20 | 31.17 |
| 80 | 25 | 50.27 |
| 100 | 25 | 78.54 |
| 125 | 32 | 122.72 |
| 160 | 40 | 201.06 |
| 200 | 50 | 314.16 |
Given: Bore = 63 mm, Rod = 20 mm, Pressure = 6 bar
Abore = π/4 × 63² = 3117 mm² = 31.17 cm²
Fextend = 6 × 10⁵ × 3117 × 10⁻⁶ = 1870 N (190.6 kgf)
Aannular = π/4 × (63² − 20²) = 2803 mm²
Fretract = 6 × 10⁵ × 2803 × 10⁻⁶ = 1682 N (171.4 kgf)
⚠️ Note: Actual force is reduced by 5–20% due to seal friction. Apply a safety factor when sizing cylinders for real applications.
Pneumatic cylinder extend force is F = P × A, where P is supply pressure and A is bore area (π/4 × D²). For retract force, use the annular area: A = π/4 × (D² − d²), where d is the rod diameter.
Extend force uses the full bore area and is always higher. Retract force uses the annular area (bore minus rod cross-section), giving less force. Retract speed is faster for the same flow rate since the volume is smaller.
Piston speed v = Q / A. For extend: v = Q / A_bore. For retract: v = Q / A_annular. The retract stroke is faster than extend at the same flow rate because the annular area is smaller.
A safety factor of 1.5–2.0 is typical. Seal friction reduces theoretical force by 5–20%. Also consider dynamic loads, acceleration forces, and pressure drops in the supply line.
Yes. Seal friction typically reduces theoretical force by 5–20% depending on seal type (O-ring, lip seal), lubrication, and operating speed. At low speed, breakaway friction is higher than running friction.
The procedures described on this page were developed and field-tested by the Vibromera team using the Balanset-1A, a portable dual-channel balancer and vibration analyzer for on-site rotor balancing.
Professional field balancing instruments and software. Used in 50+ countries.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
