A limiting charge is an upper limit on how much doctors who do not accept Medicare’s approved amount as payment in full can charge to people with Medicare. Federal law sets the limit at 15 percent more than the Medicare-approved amount. Some states limit it even further. For example, in New York doctors can only charge 5 percent more than Medicare’s approved amount for certain services. This charge is in addition to 20 percent coinsurance (45 percent for mental health services). Providers who opt-out of Medicare are not subject to these limiting charges and can charge as much as they want, if the patient signs an agreement with them prior to receiving care.