The Cylinder Force (Pull) calculator computes the pull force associated with a cylinder based on the pressure (P), the bore size (B), and the diameter (D) of the rod.
INSTRUCTIONS: Choose your preferred units and enter the following:
Force: The calculator returns the pull force (F) in pounds (pound force). However, this could be automatically converted to other force units via the automatic pull-down menu.
To compute the Push Force of the Cylinder, CLICK HERE.
http://www.machinedesign.com/pneumatics/guidelines-selecting-pneumatic-cylinders
http://www.engineeringtoolbox.com/hydraulic-force-calculator-d_1369.html