CalcPanel

Pneumatic Cylinder Speed Calculator #

Quickly calculate pneumatic cylinder extension and retraction speed from available air flow, bore, and rod diameter. Estimate cycle time and required valve flow coefficient (Cv). This quick calculator assumes steady-state flow; for full cylinder sizing with force and air consumption, use our cylinder sizing calculator.

Cylinder & Flow Parameters

Advanced calculator

Rod diameter sets retract (annular) area and retract speed/time.

0 = single-acting

About this calculator

Cylinder speed ≈ available free-air flow ÷ piston area (converted to actual volume at line pressure). Retract is usually faster because the rod reduces rod-end (annular) area, not the cap-end. Typical speeds: 2–20 in/s (50–500 mm/s); cushioned ends often need <4 in/s near stroke end. Assumption: steady flow fully available at the ports—real valves and tubing can cut speed 20–40%. Example: a 2 in bore, 0.5 in rod, 6 in stroke at 90 PSIG with 20 SCFM available extends at about 25.7 in/s (~0.23 s stroke). Required Cv shown is a screening estimate only—confirm with the Valve Cv calculator. Browse all pneumatic calculators.

Results

Extend Speed
25.7 in/s
Retract Speed
27.5 in/s
Extend Time
0.23 s
Retract Time
0.22 s
Full Cycle Time
0.45 s
Required Valve Cv
3.2 (screen)

Continue Your Calculation

After piston speed, verify cylinder force and air consumption, then size the supply valve Cv.

Size cylinder →

Quick Reference #

Common values and conversions for quick reference. Use these as starting points for your calculations.

ParameterImperialMetricNotes
Standard Pressure14.7 PSIA1.013 barAtmospheric at sea level
Standard Temp60F (520R)15.6C (288.7K)SCFM reference
CFM to L/s1 CFM0.4719 L/sFlow rate conversion
PSI to bar1 PSI0.06895 barPressure conversion
HP to kW1 HP0.7457 kWPower conversion

Formulas and Method #

Ideal Gas Law

P x V = n x R x T

All compressed air calculations are based on the ideal gas law, which relates pressure, volume, temperature, and amount of gas. For compressed air systems, this is used to convert between standard and actual conditions, calculate pressure drop, and determine flow rates.

Standard to Actual Conversion

ACFM = SCFM x (P_std / P_actual) x (T_actual / T_std)

Convert standard flow (SCFM) to actual flow (ACFM) at operating conditions. Actual flow is used for velocity and pressure drop calculations; standard flow is used for compressor ratings and energy calculations.

Assumptions and Limitations

This calculator provides planning-level estimates. Key assumptions: air behaves as an ideal gas (valid for pressures below 300 PSIG); standard conditions are 14.7 PSIA and 60F; no moisture or oil effects; steady-state flow. Actual results may vary based on equipment condition, altitude, temperature, and system configuration. Always verify with manufacturer datasheets and professional engineering judgment for critical applications.

Typical cylinder speeds #

ApplicationSpeed rangeDesign note
Clamping / pressing50–150 mm/sLower speed, higher force control
General automation150–400 mm/sBalance flow vs port size
Eject / lightweight400–800 mm/sAdd cushioning at stroke ends

Frequently Asked Questions #

How do you calculate pneumatic cylinder speed?

Speed = flow rate divided by effective piston area. Extend speed uses bore area: v = Q / A_bore. Retract speed uses annular area: v = Q / (A_bore - A_rod). Convert units consistently (CFM to in³/s or L/min to mm²/s) before dividing.

Why is retract speed faster than extend?

On double-acting cylinders, retract uses smaller annular area (bore minus rod), so the same air flow produces higher velocity. A 2 inch bore with 0.5 inch rod retracts about 1.07× faster than extend at equal supply flow.

How do flow controls affect cylinder speed?

Meter-out flow controls on the exhaust port stabilize speed under varying load. Meter-in controls save air but speed varies with load. Size the control valve or orifice so supply flow matches required Q = A × v at operating pressure.