A surplus variable is a non-negative variable subtracted from a greater-than-or-equal-to constraint to convert the inequality into an exact equality for standard linear programming form. It represents the excess amount by which the left-hand side of a constraint exceeds its required minimum threshold.

Surplus in Linear Programming is the amount by which the left-hand side of a “greater than or equal to (≥)” constraint exceeds the required minimum. It shows how much a resource or requirement is above the minimum level. For example, if the requirement is at least 50 units and the solution provides 60 units, the surplus is 10 units.

In Linear Programming, a surplus is the amount by which a solution exceeds the minimum required amount in a greater-than-or-equal-to (≥) constraint.

Example:

If the constraint is X₁ + X₂ ≥ 50 and the solution is 60, the surplus is:

60 − 50 = 10

So, there is a surplus of 10 units.