The cost of Part B Medicare premium varies depending on your income. For the majority of beneficiaries, the standard premium amount for 2021 is $148.50 per month. However, if your modified adjusted gross income (MAGI) as reported on your IRS tax return from 2 years ago is above a certain threshold, you may be required to pay a higher premium. The income-related monthly adjustment amount (IRMAA) is based on your tax filing status and income. For example, in 2021, if you file as an individual and your income is above $88,000, you will be required to pay a higher premium. It is essential to regularly check the official Medicare website for updates on premium costs and income thresholds. You can also consult with a Medicare representative or your local Social Security office for more information.