Hydraulic Cylinder Force Calculator
Find extension and retraction force from dimensions and pressure.
Results
Extension force
- Retraction force
- 37.7 kN37,699.1 N3,844.24 kgf8,475.1 lbf
- Piston area
- 5,026.55 mm²
- Annular area
- 3,769.91 mm²
These are theoretical forces for a single-rod cylinder. The calculation ignores seal friction, opposing chamber backpressure, pressure losses and dynamic loads. Actual available force can be lower.
Formula · How it works
Formula
A = πD² / 4; Aᵣ = π(D² − d²) / 4; F = p × APiston area A = πD²/4. Annular area Aᵣ = π(D² − d²)/4. Force F = pA, using pressure in Pa and area in m² to obtain force in N.
Worked example
For an 80 mm bore, a 40 mm rod and 100 bar pressure, piston area is 5,026.55 mm² and annular area is 3,769.91 mm². Theoretical extension force is 50.27 kN and retraction force is 37.70 kN.
How it works
Pressure acts on the full piston area during extension. During retraction, the rod occupies part of that area, leaving a smaller annular area. At equal applied pressure, retraction force is therefore lower.
Common questions
Why is retraction force lower?
The rod reduces the area exposed to pressure on the rod side. The same pressure acting over a smaller area produces less force.
Does the result include backpressure or friction?
No. It assumes no opposing pressure and no friction. For net force, subtract the opposing pressure force and account for mechanical losses.