Your insurance card is in your wallet, but the explanation of benefits sitting in your inbox might as well be written in a foreign language. Here's what the three big cost-sharing terms actually mean and how they work together over the course of a plan year.
What a Copay Is (and When You Pay It)
A copay is a flat fee you pay at the time of a visit or service: the price tag on a specific type of care under your plan.
Your plan might charge $25 for a primary care visit, $50 for a specialist, and $10 per prescription. You pay that amount regardless of what the provider bills your insurer. Some plans charge copays for urgent care, telehealth, and lab work too. The amounts vary, so check your Summary of Benefits and Coverage (SBC), a plain-language document insurers are required to provide.
One thing to know: on many plans, copays for certain services don't count toward your deductible. They may still count toward your out-of-pocket maximum (more on that below), but this varies by plan. Read the fine print in your SBC.
What a Deductible Is
A deductible is the amount you pay out of pocket for covered services before your insurance starts sharing costs with you.
Say your deductible is $1,500. For the first $1,500 of covered care in the plan year, you pay the full negotiated rate yourself. After that, your insurance kicks in and covers a share going forward. Note that costs for services your plan doesn't cover at all don't count toward your deductible, and on many plans, common services like office visits run through copays rather than the deductible anyway.
According to KFF, the average deductible for single coverage in employer-sponsored plans is over $1,700. That's a meaningful number if you hit it mid-year unexpectedly. Deductibles reset at the start of each plan year, usually January 1, though this depends on when your plan year begins.
What Coinsurance Is
Coinsurance is the percentage split between you and your insurer after you've met your deductible.
A common split is 80/20: your insurer pays 80% of the allowed amount, you pay 20%. Another common structure is 70/30. Say you've met your $1,500 deductible and then have an outpatient procedure with an allowed cost of $2,000. With 80/20 coinsurance, your insurer pays $1,600 and you owe $400.
Coinsurance is calculated on the allowed amount, the rate your insurer has negotiated with the provider, not the provider's original sticker price. If you see an out-of-network provider, that negotiated rate may not apply, and your coinsurance percentage gets applied to a higher number. That's one of the main reasons staying in-network matters financially.
How All Three Work Together in a Plan Year
These three cost-sharing pieces don't operate in isolation. Here's what a realistic plan-year scenario might look like:
- January–March: You have two primary care visits. Your plan charges a $30 copay per visit. You pay $60 total. Your deductible: still $0 applied.
- April: You need an MRI. The allowed cost is $800. You haven't met your deductible yet, so you pay the full $800 out of pocket. Deductible applied: $800 of $1,500.
- June: You need a follow-up procedure. Allowed cost: $1,200. You still owe $700 to meet your deductible, you pay that $700, then your 20% coinsurance kicks in for the remaining $500, so you owe another $100. Total out of pocket for that visit: $800. Deductible: met.
- August onward: Every covered service runs through coinsurance only. You pay 20% of the allowed cost until you hit your out-of-pocket maximum.
The Out-of-Pocket Maximum: Your Annual Ceiling
The out-of-pocket maximum (also called the out-of-pocket limit) is the most you'll pay in covered costs during a plan year. Once you reach it, your insurer covers 100% of covered, in-network services for the rest of the year. Copays, deductible payments, and coinsurance all typically count toward this maximum, but check your SBC, because not every plan is identical.
For 2025, the ACA sets limits on how high these maximums can go for marketplace plans: $9,200 for individual coverage and $18,400 for family coverage. Employer-sponsored plans must meet similar limits. Some plans set their maximums lower.
If you're managing a serious or chronic condition and expect significant healthcare use in a given year, your out-of-pocket max is one of the most important numbers to compare when choosing between plans during open enrollment.
Family Plans and Embedded vs. Aggregate Deductibles
If you're on a family plan, the structure can get more complicated.
Some plans use an embedded deductible: each person has their own individual deductible, plus a family-wide one. Once an individual hits theirs, coinsurance kicks in for that person, even if the family total hasn't been met yet. Other plans use an aggregate deductible: the entire family shares a single pool, and no individual reaches coinsurance until the family has collectively paid the full amount.
This distinction matters if one family member uses significantly more care than others. Your SBC or a call to your insurer's member services line will tell you which structure your plan uses.
Common Situations That Trip People Up
Switching plans mid-year: if you change jobs or switch coverage, your deductible usually resets. Progress toward your old plan's deductible doesn't transfer.
Out-of-network care: even with coinsurance, going out of network can mean the cost-sharing math is applied to a much higher baseline. Some plans have separate, higher out-of-network deductibles.
Preventive care: under the ACA's preventive care rules, certain preventive services must be covered at no cost to you, even before you've met your deductible. This includes annual wellness visits and certain screenings. If you're charged for something you believed was preventive, call your insurer and ask why.
Balance billing: this is when a provider bills you for the difference between their charge and your insurer's allowed amount. Federal surprise billing protections limit when this can happen for certain out-of-network services. It deserves its own post, but know that it's a separate issue from copays, deductibles, and coinsurance.
Where to go from here
If you're comparing plans during open enrollment or after a qualifying life event, knowing these numbers cold gives you a real advantage. Use the ProviderQuoHealth directory to search for in-network providers once you've confirmed your coverage. If you need a specialist and want to understand what their visits might cost, start at our specialties pages to learn what different types of providers typically do before you book.
For questions about your specific plan's cost-sharing structure, your insurer's member services line and your plan's SBC are the most reliable starting points.
Important note
This article is for general information and is not medical advice. It is not a substitute for professional care from a licensed clinician. If you have a medical concern, talk to a healthcare provider. If you are experiencing a medical emergency, call 911 (in the U.S.) or your local emergency number.