Box 12a-DD is the cost of your employer sponsored health insurance. The retirement savings credit is a credit to help some taxpayers save for retirement. See requirements below and if applicable to you, enter under the Deductions & Credits section.

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The Retirement Savings Contribution Credit (often called Saver’s Credit) is based on contributions that you have made (or will make) to either a retirement plan through your employer or to a Traditional or Roth IRA.  The amount of Saver’s Credit that you may qualify to receive is based on your income and the amount of contributions made to retirement plans.

If you have made retirement plan contributions through your employer, those will be reported in Box 12 of your W-2.  If your W-2 only shows information with the code DD and no other lines in Box 12, then that would indicate that there was no retirement plan contribution.  If you feel that this is incorrect, you should contact your employer and request a corrected W-2. 

For more specific details about the Saver’s Credit or the codes used for Box 12 of your W-2, use the links provided in the comment above.