Skip navigation

Quick Guide to Coinsurance & Copays in Medicare

Published January 21, 2022


When you enroll in Medicare, it is important to understand what it will cost you. As we explain here, Medicare has a variety of ways members share costs, including premiums and deductibles, some of which are linked to income level. There are additional costs that are charged when you actually use a service.


Coinsurance payments are shared by you and Medicare on a percentage basis. Medicare generally pays 80% for covered services and you pay 20% (unless you have a Supplemental plan which fills in most of the gaps).


Copays are set fees you pay for doctor visits or prescription drugs when you use those services.

Monthly Premiums

Normally, Medicare covers 80% of “approved services” after you have met your deductible for Part A or Part B. If you only have Original Medicare, without a Supplement of any kind, you may be responsible for the remaining 20% of the approved charge. The reason there are Supplemental plans is to provide members with the option of paying a monthly premium to fill in the gaps of what Medicare will not cover. Part C, which is called Medicare Advantage, may have lower monthly premiums than a Supplemental plan, but there are coinsurance and copays on services like hospital care, doctor visits, and lab tests.

Out of Pocket Maximums

Original Medicare does not have any limits on what you might pay annually out of pocket if the services you received were not covered or approved by Medicare. Medicare Advantage plans do have annual out-of-pocket limits (maximums) and Supplemental plans K and L also have out-of-pocket limits.

Since Medicare does not cover everything you might need, particularly if the treatment is considered experimental or investigational, you may want to consider enrolling in a plan that limits the maximum you might have to pay in any given year.

If you choose a Supplemental plan, it is important to find out what coinsurance or copays you might need to pay in addition to what the Supplemental plan covers.

Part D Prescription Drug Costs

The Part D prescription drug plans have premiums, deductibles, and copayments. The private plans that offer prescription drug coverage are not allowed to charge you more than $445 for the Part D deductible. Once you and your plan spend $4,130 combined on drugs (including the deductible), you’ll pay no more than 25% of the cost for prescription drugs until your out-of-pocket spending is $6,550, under the standard drug benefit in 2021.

OpenMedicare helps seniors navigate some of their most important decisions around health and wellness.

Get a free quote for your plan options ➡

Find the right
Medicare plan.

Enter your ZIP code to get started.