| When premium is due | Every month, regardless of care used |
| When deductible applies | Before insurer starts sharing costs |
| How a copay is calculated | Fixed flat fee per service visit |
| How coinsurance is calculated | Percentage of the actual service cost |
| Common coinsurance split | 80% insurer / 20% member |
| Out-of-pocket maximum purpose | Caps total annual cost-sharing for the member |
The Four Terms That Drive What You Pay
When you sign up for health insurance, you agree to a specific cost-sharing arrangement with your insurer. Four terms define nearly every dollar that flows between you and your plan: premium, deductible, copay, and coinsurance. Knowing what each one means — and when it applies — prevents costly surprises at the pharmacy or after a hospital visit.
Premium
The fixed amount you pay — typically monthly — to keep your insurance policy in force. It is owed regardless of whether you use any covered services.
Deductible
The dollar amount you must pay out of pocket for covered services each plan year before your insurer begins sharing costs. Plans may exempt certain services, like preventive care, from this requirement.
Copay
A flat, predetermined fee you pay for a specific covered service, such as a doctor's visit or prescription. The amount stays the same no matter what the total service costs.
Coinsurance
Your share of covered medical costs, expressed as a percentage, that you pay after meeting your deductible. For example, a 20% coinsurance means you pay one-fifth of each covered bill until you reach your out-of-pocket maximum.
Out-of-Pocket Maximum
The most you will pay in covered costs during a single plan year, combining your deductible, copays, and coinsurance. After reaching this cap, your insurer covers 100% of eligible expenses for the remainder of the year.
These terms also interact with each other. A low premium often pairs with a high deductible. A plan with copays may also charge coinsurance for certain services. The full picture only makes sense once you understand each piece separately.
For a broader look at the types of coverage these costs apply to, see the Coverage Types hub.
Premiums: Your Recurring Cost to Stay Covered
A premium is the fixed amount you pay — usually monthly — to keep your insurance policy active. You owe it whether or not you use any medical services that month. Think of it as a membership fee: it buys you access to coverage, not coverage itself.
Premiums vary widely based on your plan tier, the number of people covered, your age, and whether your employer subsidizes part of the cost. If your employer offers group insurance, you likely see your share deducted directly from your paycheck.
Skipping or missing a premium payment can trigger a grace period, after which your policy may lapse — meaning claims during that gap could be denied entirely.
Choosing the right premium level involves a real trade-off. Getting that balance wrong can cost you more than you expect over the course of a year.
Deductibles, Copays, and Coinsurance: Your Share After Care
Once you actually use your insurance, three other cost terms kick in — often in sequence.
| When premium is due | Every month, regardless of care used |
| When deductible applies | Before insurer starts sharing costs |
| How a copay is calculated | Fixed flat fee per service visit |
| How coinsurance is calculated | Percentage of the actual service cost |
| Common coinsurance split | 80% insurer / 20% member |
| Out-of-pocket maximum purpose | Caps total annual cost-sharing for the member |
Deductible
A deductible is the amount you pay out of pocket for covered services before your insurer starts sharing the cost. If your deductible is $1,500, you pay the first $1,500 of covered medical bills each plan year. After that threshold is met, your plan begins contributing.
Some services — like preventive care or specific generic prescriptions — may be covered before you meet your deductible, depending on plan rules. Always check your Summary of Benefits and Coverage document to confirm.
Copay
A copay is a flat, fixed dollar amount you pay for a specific service — say, $30 for a primary care visit or $15 for a generic drug. Copays are predictable and don't change based on the total cost of the service. In many plans, copays apply even before you've met your deductible.
Coinsurance
A coinsurance is a percentage of the cost you pay after your deductible is met. A common split is 80/20: your insurer covers 80% and you pay 20%. Unlike a copay, coinsurance scales with the actual cost of care, so a more expensive procedure means a larger out-of-pocket share.
To see how copays and coinsurance play out in real scenarios, the article Copay vs. Coinsurance: Two Cost-Sharing Structures, Very Different Outcomes walks through concrete examples.
Out-of-Pocket Maximum
One more term worth knowing: the out-of-pocket maximum is a cap on the total you'll pay in a plan year (deductibles, copays, and coinsurance combined). Once you hit it, your insurer pays 100% of covered costs for the rest of the year.
For a complete picture of what your plan will and won't pay for, see What Health Insurance Actually Covers — and What It Doesn't.
This article provides general insurance information for educational purposes only and does not constitute personalized financial, insurance, or legal advice. Coverage terms, costs, and rules vary by plan and provider. Always review your actual policy documents and consult a licensed insurance agent or adviser for guidance specific to your situation.