Health insurance can make medical care more affordable, but the terms on a plan can be confusing. A monthly premium is only one part of the cost. You may also have a deductible, copays, coinsurance and an out-of-pocket maximum. These amounts determine how much you pay when you visit a doctor, fill a prescription, receive a test or need hospital care.

The easiest way to compare plans is to understand what each term means and how the costs work together. A plan with a lower monthly premium may have a higher deductible or larger cost-sharing amounts. A plan with a higher premium may reduce what you pay when you use care. The right choice depends on your health needs, budget and the doctors and hospitals in the plan’s network.

2027 Marketplace enrollment is open now. The federal Health Insurance Marketplace open-enrollment period runs from November 1, 2026, through January 15, 2027. Enroll by December 15 for coverage that begins January 1; people who enroll from December 16 through January 15 generally start coverage February 1, after paying the first premium. State-run Marketplaces may have their own dates, so confirm the deadline where you live. HealthCare.gov’s official enrollment calendar lists the federal dates.

Costs are also changing for 2027. KFF’s November 6 analysis says finalized benchmark silver Marketplace premiums increased by an average of 13% nationally. That is a benchmark-plan average—not a prediction that every person’s bill will rise by exactly 13%. Your actual premium depends on your location, age, plan, household income and eligibility for financial assistance. Many Marketplace enrollees still qualify for subsidies, while people above 400% of the federal poverty level can face higher net costs after the enhanced premium tax credits expired. Compare your available plans and subsidy amount rather than assuming your current plan is still the best value. KFF’s 2027 enrollment analysis explains the changes.

Health insurance premiums and deductibles: what you pay before coverage

Premium: The premium is the amount you pay to keep the insurance policy active. It is usually paid monthly, whether you use medical care or not. If you receive coverage through an employer, the employer may pay part of the premium and deduct your share from your paycheck. Marketplace coverage may include a premium tax credit for eligible households, which can lower the amount paid each month.

Deductible: The deductible is the amount you pay for covered services that are subject to the deductible before the plan begins paying its share. If your deductible is $2,000, you generally pay the first $2,000 of eligible costs before coinsurance begins. But not every service is necessarily subject to the deductible. Many plans cover certain preventive services before the deductible, and some plans charge a copay for primary-care visits or prescriptions before the deductible is met.

Some plans have separate deductibles for individuals and families. A family deductible may be an aggregate amount that applies to the whole household, or the plan may have individual limits within the family plan. Read the Summary of Benefits and Coverage to see how the deductible works for each person and for the family as a whole.

Network: A network is the group of doctors, hospitals, pharmacies and other providers that have contracted with the insurer. In-network providers generally agree to negotiated rates. Out-of-network care can cost more and may not count toward the plan’s out-of-pocket maximum. Some plan types, such as HMOs and EPOs, restrict out-of-network coverage except for emergencies, while PPOs may offer more flexibility at a higher cost.

HealthCare.gov explains that the deductible is what you pay for covered health care services before your insurance plan starts to pay, with exceptions for services that are covered before the deductible. See its deductible definition and premium definition.

Copays and coinsurance: how your share of a medical bill is calculated

Copay: A copay is a fixed dollar amount you pay for a covered service, such as $25 for a primary-care visit or $15 for a prescription. The amount can differ by service, provider type or drug tier. A copay may be due when you receive care, and the plan may or may not require you to meet a deductible first for that service.

Coinsurance: Coinsurance is the percentage of the allowed cost you pay for a covered service after any applicable deductible has been met. If your plan has 20% coinsurance for a service with a $1,000 allowed amount, your share is $200 and the insurer pays the remaining $800, assuming the service is covered and no other plan rule changes the calculation.

Here is a simplified example. Imagine a plan has a $2,000 deductible, then 20% coinsurance for a covered hospital service. If you have not met the deductible and receive a service with a $1,000 in-network allowed amount, you generally pay the $1,000. If you later receive another $1,000 covered service after the deductible has been met, your 20% coinsurance would be $200 and the plan would pay $800. Actual bills can be more complicated because some services have copays, separate deductibles or exclusions.

The allowed amount is the price the insurer recognizes for a covered service. It may be lower than the provider’s billed charge. In-network providers generally accept the negotiated allowed amount, while out-of-network providers may bill you for amounts above what the plan recognizes, depending on the plan and applicable law.

Preventive care is another important exception. Many non-grandfathered health plans must cover a list of recommended preventive services at no cost when provided in-network, even if you have not met your deductible. That can include certain screenings, immunizations and preventive visits. A service may not be treated as preventive if it is provided to diagnose or treat an existing condition, so ask the provider how the visit will be billed.

HealthCare.gov provides definitions for copayments, coinsurance and preventive care benefits. These official definitions can help you compare how different plans apply cost-sharing.

Out-of-pocket maximum: the most you pay for covered care in a plan year

The out-of-pocket maximum is the most you pay during a plan year for covered services that count toward the limit. It generally includes your deductible, copays and coinsurance for eligible in-network care. After you reach the limit, the plan pays 100% of the allowed cost of covered benefits for the rest of that plan year.

The limit does not include your monthly premiums. It also generally does not include out-of-network care, services the plan does not cover or amounts above the allowed charge. If you receive care outside the network or choose a service excluded by the plan, you may still owe money after reaching the out-of-pocket maximum.

For 2027 Marketplace plans, HealthCare.gov lists a maximum out-of-pocket limit of $12,000 for an individual and $24,000 for a family. Those are federal maximum limits for the applicable Marketplace coverage—not the amount every plan charges. A plan can have a lower limit, and other types of coverage may follow different rules. For comparison, the 2026 Marketplace maximum was $10,600 for an individual and $21,200 for a family.

For 2027 Marketplace coverage, the federal open-enrollment deadline is January 15, 2027. December 15 is the key date if you want coverage to begin January 1. If you are shopping now, compare the full annual cost—not just the monthly premium—including the deductible, prescription coverage, provider network and maximum out-of-pocket amount. The federal limit for most Marketplace plans is $12,000 for an individual and $24,000 for a family in 2027, up from $10,600 and $21,200 in 2026. See HealthCare.gov’s current out-of-pocket limit guidance before choosing a plan.

When comparing plans, look at the premium, deductible, copays, coinsurance and out-of-pocket maximum together. A low-premium plan can cost more if you need frequent appointments, prescriptions or specialist care. A higher-premium plan may provide more predictable costs if you expect to use a lot of covered services. Check the provider network and prescription formulary as well; a low deductible is less helpful if your preferred doctor or medication is not covered on favorable terms.

Before receiving scheduled care, ask the insurer whether the service is covered, whether prior authorization is required, whether the provider is in-network and what your estimated share will be. After the service, compare the provider’s bill with the insurer’s Explanation of Benefits (EOB). The EOB is not a bill, but it shows how the insurer processed the claim and what amount may be your responsibility.

Health insurance is easier to compare when you know which costs are fixed, which depend on the service and which are capped. The premium keeps the plan active; the deductible is what you pay before certain benefits begin; a copay is a fixed amount; coinsurance is a percentage; and the out-of-pocket maximum limits eligible cost-sharing. Reading those details before enrolling can help prevent expensive surprises when you need care.