Tax deductions with Medical aid

How do you calculate Tax when there is a medical aid deduction where the full contribution is from the employee and none from the company?
Eg. Gross Salary: R18400
-Deduction - Medical Aid: R2018
-Deduction - Tax:?

Without the medical aid I worked out Tax deduction should be - R2466

Please make use of our Medical Tax Credits Calculator to work out what the credit will be.