How this calculator works
Plan year: 2026, United States. Medicare premiums rise in steps when modified adjusted gross income exceeds the first threshold. The income used is normally from two years earlier, so 2026 premiums look at 2024 returns. For a single filer the first threshold is $109,000; for a joint return it is $218,000. Married filing separately has its own short table. The calculator adds the income-related adjustment to the standard Part B premium of $202.90 and shows the separate Part D adjustment, which is added to whatever Part D plan premium you pay. The model leaves out the Part D plan premium itself, the Part A premium, late enrolment penalties, the life-changing event appeal process, Medicare Advantage plan premiums and any tax on benefits. It assumes full Part B coverage.
Formula
Find the filing-status row in the 2026 IRMAA table that contains modified adjusted gross income. The Part B premium and the Part D adjustment for that row are added. Annual amount = (Part B premium + Part D adjustment) x 12. The surcharge share = (Part B premium - 202.90) / 202.90.
Worked example
A single filer with $150,000 of modified adjusted gross income falls in the third tier. The Part B premium is $405.80 and the Part D adjustment is $37.50, so the combined monthly amount is $443.30 and the annual amount is $5,319.60. The Part B surcharge is $202.90, or 100% above the standard premium.
Frequently asked questions
Which year of income is used?
Usually the tax return from two years earlier. A 2026 premium is based on 2024 modified adjusted gross income. Social Security can use a more recent return if you file an appeal for a life-changing event such as retirement or marriage.
Is the Part D amount the whole premium?
No. It is only the income-related adjustment. Your Part D plan sets its own premium, and the adjustment is added to it. The amount is zero in the first tier.
What counts as modified adjusted gross income?
Adjusted gross income plus tax-exempt interest. It is not the same as taxable income, so deductions do not reduce it.
Do the thresholds change each year?
The income thresholds and the premium amounts are updated annually. This page uses the 2026 figures published by CMS, and later years will have different numbers.