Most people know Medicare comes in “Parts” — but when you actually need care, the difference between Part A and Part B matters enormously. Part A covers your hospital stays. Part B covers everything else. Understanding which is which means no surprise bills and no gaps in your coverage when you need it most.
- Part A = hospital insurance (inpatient care, skilled nursing, hospice, some home health)
- Part B = medical insurance (doctor visits, outpatient care, preventive screenings)
- Most people get Part A free; Part B costs $185/month in 2025
- Both parts have deductibles and cost-sharing — there’s no out-of-pocket maximum
- Together, Parts A and B are called “Original Medicare”
Medicare Part A: Hospital Insurance
Part A covers care you receive as an inpatient — when you’re formally admitted to a hospital, skilled nursing facility, or hospice. The word “admitted” matters: if you’re in the hospital but listed as “under observation,” Part A doesn’t apply the same way.
What Part A Covers
- Inpatient hospital care (semi-private room, meals, nursing, medications during stay)
- Skilled nursing facility care (up to 100 days after a 3-day hospital admission)
- Hospice care (for terminal illness with 6-month prognosis)
- Some home health care (after a qualifying hospital stay)
- Inpatient mental health care
Part A Costs in 2025
| Service | What You Pay in 2025 |
|---|---|
| Monthly premium | $0 (if 40+ work quarters) or $518/month |
| Hospital deductible (per benefit period) | $1,676 |
| Hospital days 1–60 | $0 coinsurance (after deductible) |
| Hospital days 61–90 | $419/day |
| Hospital days 91+ (lifetime reserve days) | $838/day |
| Skilled nursing days 1–20 | $0 |
| Skilled nursing days 21–100 | $209.50/day |
Medicare Part B: Medical Insurance
Part B covers almost everything that happens outside the hospital — your routine doctor visits, specialist appointments, lab work, X-rays, and preventive care. It also covers some outpatient procedures and durable medical equipment (canes, walkers, blood sugar monitors).
What Part B Covers
- Doctor visits (primary care and specialists)
- Outpatient surgery and procedures
- Lab tests, X-rays, MRIs
- Preventive screenings (mammograms, colonoscopies, flu shots — often at $0 to you)
- Durable medical equipment
- Outpatient mental health services
- Some home health services
- Ambulance services
Part B Costs in 2025
| Cost Item | Amount |
|---|---|
| Monthly premium | $185.00 (standard; more for high earners) |
| Annual deductible | $257 |
| Coinsurance after deductible | 20% of Medicare-approved amount |
| Preventive services | $0 (no deductible required) |
Part A vs Part B: Key Differences at a Glance
| Feature | Part A | Part B |
|---|---|---|
| What it covers | Hospital / inpatient | Medical / outpatient |
| Monthly premium | $0 for most people | $185/month (2025) |
| Annual deductible | $1,676 per benefit period | $257 per year |
| Out-of-pocket max | None | None |
| Enrollment | Usually automatic at 65 | Must actively enroll |
Frequently Asked Questions
Do I need both Part A and Part B?
Most people enroll in both. Part A is free for most and covers hospital care. Part B covers the far more common outpatient and doctor visit expenses. Having only Part A leaves major gaps.
What if I’m still working at 65?
If you have employer coverage from a 20+ employee company, you may delay Part B without penalty. But you should generally enroll in Part A since it’s free. Talk to your HR department before making this decision.
Is there an out-of-pocket maximum with Original Medicare?
No — this is one of Original Medicare’s biggest weaknesses. There’s no cap on what you can pay. A serious illness or extended hospital stay could cost tens of thousands. Consider adding a Medigap plan or Medicare Advantage plan with an out-of-pocket maximum.
Bottom Line
Part A and Part B work together to form your Original Medicare coverage. Part A handles the hospital; Part B handles the doctor. Both have deductibles, both have gaps, and neither has an out-of-pocket maximum — which is why supplemental coverage is so important for most seniors.
