Reserve Component Employer Incentive, Compensation, and Relief Act of 2018 This bill amends the Internal Revenue Code to allow a tax credit for certain employers of reservists (i.e., members of the National Guard or a reserve component of the Armed Forces). The tax credit is equal to $1,000 for each reservist employed during the year, plus an additional amount that ranges from $3,000 to $10,000, depending on the number of days the reservist serves in the uniformed services during the year.