Computes force in Newtons between a solenoid and ferromagnetic material separated by gap g.  

F = (Fm)2 μ0 A / (2 g2)

F = (N * I)2 μ0 A / (2 g2)

Where: 

Any units may be used for A and g if consistent.  E.g. in2 and in, or m2 and m. 

Solenoid Force Calculator
I (Current In Amps.) (A)
N (turns)
(Length units2)
g (Length units)
Results

F (N) (LBS)