Responsible Additions and Increases to Sustain Employee Health Benefits Act of 201 8 This bill amends the Internal Revenue Code, with respect to the tax exclusion for distributions from health flexible spending arrangements provided under a cafeteria plan, to: (1) increase the annual limit on employee salary reduction contributions to $5,000, with an additional $500 for each additional employee dependent above two dependents that has not been taken into account by another person for the year; (2) revise the adjustment for inflation after 2018; and (3) allow a carryforward into the next year for unused amounts in such plans.