Excel Solver - Add, change or delete a Constraint

Add a constraint

Change or delete a constraint

1. In the Solver Parameters dialog box, under Subject to the Constraints, click Add.
2. In the Cell Reference box, enter the cell reference or name of the cell range whose value(s) you want to constrain.  You can use a single cell or a cell range, but not multiple ranges.
3. Click the relationship ( <=, =, >=, int, bin, or dif ) that you want between the referenced cell(s) and the constraint.
   • If you click int, integer appears in the Constraint box.
   • If you click bin, binary appears in the Constraint box.
   • If you click dif, alldifferent appears in the Constraint box.
4. In the Constraint box, type a number, a cell reference or name, or a formula.  For best performance and best results in Solver reports, use a number, or a reference or name of a cell or cells that contain numbers.  Use only the dropdown list to select integer, binary or alldifferent – do not type these words.  A constraint such as A1:A3 <= 10 is shorthand for A1 <= 10, A2 <= 10, A3 <= 10.  A constraint such as A1:A3 <= B1:B3 is shorthand for A1 <= B1, A2 <= B2, A3 <= B3.
5. Do one of the following:
   • To accept the constraint and add another, click Add.
   • To accept the constraint and return to the Solver Parameters dialog box, click OK.
6. NOTES
   • You can apply the int, bin or dif relationships only in constraints on decision variable cells.
   • When the Simplex LP Solving Method is selected, there is no limit on the number of constraints. When the GRG Nonlinearor Evolutionary Solving Method is selected, there is a limit of 100 constraints, in addition to bounds and int, bin or dif restrictions on the variables.
7. In the Solver Parameters dialog box, under Subject to the Constraints, click the constraint that you want to change or delete.
8. Click Change and then make your changes, or click Delete.