You will likely have to pay a penalty for signing up late. Missing your Initial Enrollment Period can be costly with Medicare Part A, Part B and Medicare Part D potentially charging premium penalties. Medicare Part A Premium Penalty: Part A is premium free if you or your spouse worked and paid taxes for at least 10 years. If you have to enroll in Part A and didn’t sign up when you were first eligible, the penalty for late enrollment is 10%. The Part A premium penalty is charged for twice the number of years you delay enrollment. For example, if you wait two years, you’d pay 10% for 4 years (2 x 2). The penalty applies no matter how long you delay Part A enrollment. Medicare Part B Premium Penalty: In most cases, if you don’t sign up for Part B when you’re first eligible, you’ll have to pay a late enrollment penalty. The penalty for late enrollment in Part B is an additional 10% for each 12-month period you delay. You’ll have to pay this penalty for as long as you have Part B. For example, if your Initial Enrollment Period ended September 30, 2016 and you enrolled in Part B during the General Enrollment Period March 2019, your late enrollment penalty would be 20% of the Part B premium (2 x 10%) because you waited 30 months to sign up, which includes two full 12-month periods. You can typically avoid a late enrollment penalty if you meet certain criteria that allows you to sign up for Part B during a Special Enrollment Period. Medicare Part D Premium Penalty: The penalty for late enrollment in a Part D plan is 1% of the average Part D premium for each month you delay enrollment. The amount is added to your Medicare Part D monthly premium, which occurs for as long as you’re enrolled in a Medicare Part D plan. You may delay enrolling in Medicare Part D without penalty if you qualify for Extra Help or have creditable drug coverage. If it’s been more than 63 days since you’ve had creditable coverage, then the penalty may apply.