Deductible, Copay, Coinsurance and Out-of-Pocket Maximum Explained

Health insurance has its own vocabulary, and the same few words show up on every plan: premium, deductible, copay, coinsurance and out-of-pocket maximum. They each describe a separate piece of what you pay, and understanding how they fit together is the difference between a plan that works for you and a surprise bill. This guide explains each in plain English, shows them working on one example, and lists the federal limits for 2026 and 2027.

The five terms

• Premium: the fixed amount you pay every month to keep coverage, whether or not you use care. It does not count toward your deductible or out-of-pocket maximum.
• Deductible: the amount you pay for covered services in a plan year before the plan starts paying its share. Preventive services and some other services are covered before you reach it.
• Copayment (copay): a fixed fee for a service, such as $30 for a primary care visit or $15 for a generic prescription. Depending on the plan, it may or may not count toward the deductible.
• Coinsurance: your percentage share of a covered cost after the deductible is met. With 20% coinsurance, on a $1,000 allowed charge the plan pays $800 and you pay $200.
• Out-of-pocket maximum: the most you will pay in the plan year for covered in-network care. Once reached, the plan pays 100% of covered in-network costs. It includes your deductible, copays and coinsurance but not premiums, out-of-network balance bills or services the plan does not cover.

An example from start to finish

Mina has a plan with a $2,000 deductible, 20% coinsurance, a $6,000 out-of-pocket maximum and $30 specialist copays that do not count toward the deductible. In February she has an MRI with an allowed amount of $1,500: she pays all $1,500 because the deductible has not been met. Her deductible left is $500. In April she has surgery with an allowed charge of $20,000. She pays the remaining $500 deductible, then 20% of the other $19,500, or $3,900, for a total of $4,400. Her cost so far is $1,500 + $4,400 = $5,900, close to her maximum of $6,000. In June, a $5,000 physical therapy series costs her just $100 (the remaining room) and the plan pays the rest. After that, the plan pays everything covered and in network for the rest of the year. On January 1 the counters reset to zero, which is why the calendar matters when you schedule care.

Allowed amount versus billed amount

Hospitals and doctors bill a list price that few people ever pay. Your plan has negotiated rates (the “allowed amount”) with in-network providers. Your deductible and coinsurance are based on the allowed amount. If an out-of-network provider charges more than the allowed amount, you may be “balance billed” for the difference, except in cases protected by the No Surprises Act.

Individual and family limits

On a family plan, there are usually two sets of numbers: an individual deductible and maximum, and a family deductible and maximum. In an embedded design each person is covered once they reach their own individual deductible, while in an aggregate design the family must pay the whole family deductible before the plan pays for anyone (except preventive care). Federal law requires that no one in a family plan pays more than the individual out-of-pocket limit, even if the family limit is higher.

Federal limits on the out-of-pocket maximum

An individual plan or an employer plan that is not “grandfathered” cannot have a higher out-of-pocket maximum than these limits. Many plans have lower ones, and plans with cost-sharing reductions have even lower ones. HSA-eligible high-deductible plans have an additional, lower limit set by the IRS ($8,500 self-only and $17,000 family in 2026; $8,700 and $17,400 in 2027).

What is covered before the deductible

Under the ACA, non-grandfathered plans must cover a set of preventive services with no cost sharing when you use an in-network provider, even if you have not met your deductible. This includes many screenings, immunizations and annual wellness visits. Many plans also choose to cover primary care visits, generic drugs or telehealth with just a copay before the deductible. Look at the Summary of Benefits and Coverage for a line that says “deductible does not apply.”

How to use the terms to choose a plan

If you expect little care, the premium and the deductible matter most, because you will pay both and probably nothing else. If you expect a hospital stay, a pregnancy or ongoing treatment, the out-of-pocket maximum matters most, because you will hit it, and your cost is roughly premiums plus the maximum. If you take regular medication, copays and drug tiers matter more than the deductible. The deductible and coinsurance calculator lets you try a specific bill, and the plan comparison adds up the whole year.

Common traps

• Confusing a copay with a deductible. A $30 copay visit may still leave you owing the full price of tests and labs ordered that day.
• Forgetting separate deductibles for prescriptions or out-of-network care.
• Assuming a low deductible means low cost. A plan with a $500 deductible may have a premium that is thousands higher.
• Counting on the maximum for out-of-network care. Out-of-network amounts often have a separate, higher maximum or none at all.

Reading your own plan documents

Every plan must give you a Summary of Benefits and Coverage in a standard format. The first page has the important numbers: the overall deductible, the out-of-pocket limit, and a list of services that are not subject to the deductible. A table of common medical events then shows what you pay for a primary care visit, a specialist, a generic drug, an emergency room visit and a hospital stay. It also has coverage examples for having a baby and for managing type 2 diabetes, with the total cost of each under that plan, which is a useful point of comparison. If something is unclear, call the number on the back of your card and ask for the answer in writing. When you get a bill, use the Explanation of Benefits to confirm that the amounts assigned to the deductible, coinsurance and copay match what your plan says.