A copay, or copayment, is the fixed amount you pay for a covered health care service.
Health plans may set different copays for office visits, specialist appointments, prescription drugs, laboratory work, or emergency care. The amount is usually stated in dollars, such as $20 for a primary-care visit, rather than as a percentage of the bill.
Copays are one form of cost sharing. A deductible is the amount a patient generally pays for certain covered services before the plan begins sharing costs, while coinsurance is usually a percentage of the allowed charge. A premium is the recurring amount paid to maintain coverage, whether or not medical care is used.
Plan design can make the distinctions less tidy in practice. Some services have copays before the deductible, while others require the deductible first. In-network copays are often lower than out-of-network charges, and plans may use separate copay schedules for generic, preferred-brand, and specialty medicines.