For each 12-month period you delay enrollment in Medicare Part B, you will have to pay a 10% Part B premium penalty, unless you have insurance based on your or your spouse’s current work (job-based insurance) or are eligible for a Medicare Savings Program (MSP).
In most cases, you will have to pay that penalty every month for as long as you have Medicare. If you are enrolled in Medicare because of a disability and currently pay premium penalties, once you turn 65 you will no longer have to pay the premium penalty.
How do you calculate your premium penalty?
Let’s say you turned 65 in 2013, and you delayed signing up for Part B until 2021 (and you did not have employer insurance, which allows you to delay enrollment). Your monthly premium would be 70% higher for as long as you have Medicare (7 years x 10%). Since the base Part B premium in 2021 is $148.50, your monthly premium with the penalty will be $245.82 ($148.50 x 0.7 + $148.50).
Note: Although your Part B premium amount is based on your income, your penalty is calculated based on the base Part B premium. The penalty is then added to your actual premium amount.