Let's start with the myth that trips up almost everyone: Medicare is not free. It's valuable coverage, but it comes with monthly premiums, deductibles, copays, and out-of-pocket costs — and a lot of people don't discover this until their first medical bill arrives. This guide walks through what you actually pay, so there are no surprises.

One important note before the numbers: specific dollar amounts change every year. So this explains how the costs work — the structure that stays the same — and points you to Medicare.gov for the current-year figures. That way you understand the shape of your costs, then confirm the exact amounts.

Part A (Hospital Insurance)

  • Most people pay $0 in premiums for Part A. If you or your spouse worked and paid Medicare taxes for at least 10 years (40 quarters), Part A is premium-free.
  • If you didn't work long enough, you can still buy Part A, but you'll pay a monthly premium (the amount depends on how many quarters you worked).
  • Part A still has a deductible for hospital stays, and coinsurance kicks in for longer stays — so “premium-free” doesn't mean “cost-free” when you're actually hospitalized.

Part B (Medical Insurance)

  • Part B has a monthly premium that most people pay (it's set each year, and it's usually deducted from your Social Security check).
  • It also has an annual deductible, and after that, Medicare typically pays 80% of approved costs while you pay the remaining 20% — with no cap. More on that gap below.

The gap that surprises people: no out-of-pocket maximum

Here's the single most important cost fact about Original Medicare: it has NO out-of-pocket limit. Private insurance you had before Medicare almost certainly capped your annual spending. Original Medicare does not. That 20% coinsurance has no ceiling — so on a very large medical event, your share can climb with no upper bound.

This is exactly why most people add coverage: a Medigap policy (to cover those out-of-pocket gaps) or a Medicare Advantage plan (which builds in an annual out-of-pocket cap). Deciding which is its own topic — but the reason both exist is this uncapped gap.

Part D (Prescription Drugs) has its own costs

Original Medicare generally doesn't cover most prescription drugs, so you'd add a Part D plan (standalone, or built into a Medicare Advantage plan). Part D has its own premium, and its costs move through phases during the year (a deductible phase, then a coverage phase, then a catastrophic phase where your costs stop). The exact thresholds change annually — but the good news is that recent changes added a hard cap on your annual out-of-pocket drug costs, which didn't used to exist. Check Medicare.gov for this year's specific numbers.

Extra costs (and extra help) depending on your income

Your income can push your costs up or down:

  • Higher incomes pay more (IRMAA). If your income is above certain thresholds, you'll pay an income-related surcharge on your Part B and Part D premiums, called IRMAA. Useful to know: IRMAA is based on your income from a couple of years back, so if your income dropped (say, because you retired), you can appeal to have it lowered.
  • Lower incomes can pay less. Programs like Extra Help, Medicaid, and Medicare Savings Programs can significantly reduce — or even eliminate — premiums and out-of-pocket costs for people who qualify. If money is tight, it's genuinely worth checking whether you're eligible.

The bottom line

  • Medicare is not free — plan for premiums, deductibles, and coinsurance.
  • Part A is premium-free for most people; Part B has a monthly premium and a 20% coinsurance with no cap.
  • That missing out-of-pocket cap is the main reason people add Medigap or Medicare Advantage.
  • Part D covers drugs and now includes an annual out-of-pocket cap.
  • Your income can raise your costs (IRMAA) or lower them (Extra Help / Medicaid).
  • Because exact dollar amounts change yearly, always confirm current figures at Medicare.gov.

Understanding how these costs are structured is what lets you plan instead of getting blindsided. The part worth talking through is which additional coverage makes sense for your budget and health — because the right setup can turn Medicare from a source of financial anxiety into something predictable.