A plan with 30% coinsurance after deductible means you pay 30% of every covered medical bill once you’ve paid enough out of pocket to satisfy your annual deductible. Your insurance picks up the remaining 70%. This split continues until you hit your plan’s out-of-pocket maximum for the year, at which point your insurer covers 100% of your care.
How the Payment Sequence Works
Health insurance costs follow a specific order each plan year. First, you pay the full price of covered services until you reach your deductible (a fixed dollar amount, like $1,500 or $3,000). Once that threshold is met, your coinsurance kicks in. From that point forward, you and your insurer split every bill according to your coinsurance percentage. With 30% coinsurance, you pay 30 cents of every dollar and your plan pays 70 cents.
This continues until your total spending for the year, including your deductible and coinsurance payments, reaches your plan’s out-of-pocket maximum. For 2025, Marketplace plans cap that limit at $9,200 for an individual and $18,400 for a family. Once you cross that line, your insurer pays 100% of covered services for the rest of the plan year.
What 30% Coinsurance Looks Like in Dollars
Your 30% isn’t calculated on the full amount the hospital or doctor charges. It’s based on the “allowed amount,” which is the rate your insurance company has negotiated with the provider. This is almost always lower than the sticker price on the bill.
Here’s an example. Say you’ve already met your $2,000 deductible and then need a procedure. The hospital bills $10,000, but your insurer’s negotiated rate with that hospital is $6,000. Your 30% coinsurance applies to the $6,000, not the $10,000. You’d owe $1,800, and your plan would pay $4,200. The remaining $4,000 difference between the billed charge and the allowed amount is written off entirely; you don’t owe it.
For a smaller expense like a $200 specialist visit (at the allowed amount), your share would be $60. These costs add up over the course of a year, which is why the out-of-pocket maximum exists as a safety net.
Why 30% Is on the Higher End
Many employer and Marketplace plans use 20% coinsurance, so a 30% split means you’re shouldering a larger share of each bill. Plans with higher coinsurance rates typically come with lower monthly premiums, which makes them attractive if you’re generally healthy and don’t expect many medical expenses. But if you end up needing significant care, you’ll pay more per service before reaching your out-of-pocket limit.
To put it in perspective: on a $5,000 allowed amount for a hospital stay, someone with 20% coinsurance owes $1,000. With 30% coinsurance, that same stay costs you $1,500. Over several medical events in a year, the difference can amount to thousands of dollars.
In-Network vs. Out-of-Network Rates
The 30% coinsurance listed on your plan summary almost certainly applies to in-network providers. If you go out of network, your coinsurance rate will typically jump higher, sometimes to 40% or 50%. On top of that, out-of-network providers haven’t agreed to your insurer’s negotiated rates, so the allowed amount may be lower than what the provider actually charges. You could be responsible for the gap between what your plan pays and what the provider bills, a practice called balance billing. Staying in network protects you from both the higher percentage and the billing surprises.
Coinsurance vs. Copays
Coinsurance and copays both represent your share of a medical bill, but they work differently. A copay is a flat fee you pay at the time of service, like $30 for a primary care visit or $50 for a specialist. The amount is fixed regardless of what the visit actually costs. Coinsurance is a percentage, so what you owe scales with the price of the service. A 30% coinsurance on a $200 visit is $60, but 30% on a $5,000 procedure is $1,500.
Many plans use both. You might have copays for routine office visits and prescriptions, while coinsurance applies to larger expenses like imaging, surgeries, and hospital stays. Your plan’s Summary of Benefits and Coverage spells out which services use which cost-sharing method.
Services That Skip the Deductible Entirely
Certain preventive services are covered at no cost to you regardless of whether you’ve met your deductible. Under federal rules, most health plans must cover immunizations, cancer screenings, blood pressure checks, and other routine preventive care with zero copay or coinsurance. This means your 30% coinsurance doesn’t apply to an annual wellness exam or a standard screening mammogram. It only kicks in for diagnostic or treatment-related services after your deductible is satisfied.
Tracking Your Spending Through the Year
Your insurer tracks how much you’ve spent toward your deductible and out-of-pocket maximum. You can usually find a running total on your insurer’s website or app. Every Explanation of Benefits statement you receive after a claim also shows your progress. Keeping an eye on these numbers helps you anticipate costs, especially if you’re planning an elective procedure or know you’ll need ongoing treatment. Once your deductible is met, you’re in the coinsurance phase, and every service will cost you 30% of the allowed amount until you reach your annual cap.