Medicare Basics: Parts A, B, C and D Explained
Medicare is four programmes with one name. Missing an enrolment window can cost you a surcharge for life.
At a glance
Figures checked 1 Sep 2026
What to take away
- Part A covers hospital care, Part B outpatient care, Part C bundles them privately, Part D covers prescriptions.
- The standard Part B premium for 2026 is $202.90 a month, deducted from Social Security payments where applicable.
- Late enrolment in Part B or Part D carries a permanent premium surcharge.
| Part | Covers | Typical cost |
|---|---|---|
| A | Inpatient hospital, skilled nursing, hospice | Usually no premium with a 40-quarter work history |
| B | Doctor visits, outpatient, equipment | $202.90/month standard for 2026 |
| C (Advantage) | A and B, often D, through a private plan | Varies; often low or zero extra premium |
| D | Prescription drugs | Varies by plan |
Enrolment timing
Your initial enrolment period spans seven months around your 65th birthday. If you are still working with credible employer coverage you can usually delay Part B without penalty, but the rules depend on employer size, and getting it wrong attaches a surcharge to your premium permanently.
Contributions to an HSA must stop once Medicare begins. Enrolment can be backdated up to six months, so plan the final HSA contribution carefully to avoid an excess contribution penalty.
What Medicare does not cover
Routine dental, vision and hearing are largely excluded from original Medicare, as is long-term custodial care. Those gaps are what supplement policies and Advantage plans are competing to fill.
Common questions
There is no premium if you or a spouse paid Medicare taxes for 40 quarters. Deductibles and coinsurance still apply to hospital stays.
Usually yes, because the late-enrolment penalty is permanent and rises with each month you delay. A minimal plan is cheap insurance against that.