Binding? Not Binding?

Question

I ran a solver in excel, and on the answer report there were several of my constraints listed as "Binding" and several listed as "Not Binding", I was wondering what this means?

Answer 1

Let's say that you have set a maximum of 9000 for one of the changing cells (the constraint for this cell is <= 9000).

When Solver finds a solution, the cell could be maxed out at 9000. This means the cell value has been pushed to its limit. Perhaps a better solution could have been found if the cell was allowed to go over the limit of 9000, but because of the constraint that's not possible. In this situation, the constraint is binding.

It's also possible that the cell remains below 9000, e.g. it's only 7500 for the optimal solution. The cell value could theoretically be increased, but other contraints prohibit this. In this situation, this constraint is not binding.

Answer 2

Thank you, the report now makes a lot more sense.