On a plan that lists 0% coinsurance after the deductible, you pay nothing toward the cost of a covered in-network service once you’ve met your annual deductible. The insurer pays the full allowed amount, and your share of the bill is zero for the rest of the plan year. Coinsurance is the percentage split between you and your plan, so setting your side at zero means the plan absorbs 100% of what it has agreed to pay the provider.
What the 0% Actually Covers
Coinsurance is calculated against your plan’s allowed amount for a service, not the provider’s sticker price. The allowed amount is the maximum the insurer has agreed to pay, sometimes called the negotiated rate or eligible expense. If the allowed amount for an office visit is $100 and your coinsurance is 20%, you owe $20. At 0%, you owe nothing, and the insurer pays the full $100.1HealthCare.gov. Coinsurance – Glossary
That distinction matters because a provider’s billed charge can be higher than the allowed amount. If a doctor charges $150 and the allowed amount is $100, your 0% rate only zeros out your share of that $100. With in-network providers, you’re generally protected from paying the gap. Out-of-network, the gap can land on you even when your coinsurance is 0%.
How the Deductible Switches It On
Your coinsurance rate does not take effect until you’ve paid your full annual deductible. Before that point, you pay the entire allowed amount for every covered service out of pocket.1HealthCare.gov. Coinsurance – Glossary So on a plan with a $2,000 deductible and 0% coinsurance after it, your first $2,000 of covered care is on you, and from the next dollar forward the plan covers 100%.
The switch is automatic. You don’t file anything or notify the insurer. The claims system recognizes that you’ve hit the deductible and starts applying the 0% rate on the next claim.
Deductibles and other cost-sharing amounts reset at the start of each plan year. Most plans run on the calendar year and reset on January 1, but some employer plans use a different start date. Check your Summary of Benefits and Coverage for the exact reset date, because on that date your deductible counter goes back to zero and you start paying toward it again before the 0% rate returns.
What You May Still Owe
A 0% coinsurance rate does not necessarily mean a $0 bill. A few other charges can still apply.
Copays. A copayment is a flat dollar amount for a service, separate from coinsurance. A plan can list 0% coinsurance for a specialist visit and still charge a $50 copay each time. Your Summary of Benefits shows a dollar figure for copays and a percentage for coinsurance; look at both columns. Both count toward your annual out-of-pocket maximum.
Premiums. Your monthly premium is not cost-sharing and never counts toward the deductible or out-of-pocket maximum. You keep paying it regardless of your coinsurance rate.
Non-covered services. If the plan doesn’t cover a service at all, the 0% rate is irrelevant. You pay the full price, and none of it counts toward the deductible or the out-of-pocket maximum.
Charges above the allowed amount. Even with an in-network provider, anything above the plan’s negotiated rate is excluded from cost-sharing calculations.
The Out-of-Pocket Maximum Backstop
Every ACA-compliant plan has an annual out-of-pocket maximum, a ceiling on what you can be required to pay for covered in-network care in a single plan year. Your deductible, copays, and coinsurance all count toward it. Once you hit the cap, the plan pays 100% of covered in-network services for the rest of the year, regardless of what your coinsurance rate was.2HealthCare.gov. Out-of-pocket maximum/limit – Glossary On a plan that already pays 0% after the deductible, you often won’t need the backstop, but it’s there if a copay-heavy year pushes your total spending up.
Network Rules
The 0% coinsurance rate applies only when you use in-network providers. Out-of-network care usually carries a higher coinsurance rate, a separate and often larger out-of-pocket maximum, or no coverage at all.3HealthCare.gov. Out-of-network coinsurance – Glossary Out-of-network providers can also balance bill you for the difference between their full price and what the insurer pays, and that extra charge does not count toward your in-network out-of-pocket maximum.
Verify network status before scheduling care. Directories change between plan years and sometimes mid-year.
No Surprises Act Protections
Federal law carves out an exception. Under the No Surprises Act, emergency services at an out-of-network facility cannot cost you more than your in-network cost-sharing amount. The law also covers certain non-emergency services performed by out-of-network providers at in-network facilities, such as an out-of-network anesthesiologist or radiologist working at your in-network hospital.4Centers for Medicare & Medicaid Services. No Surprises: Understand Your Rights Against Surprise Medical Bills In those situations, what you pay counts toward your in-network deductible and out-of-pocket maximum, so your 0% rate kicks in on the same schedule it would have otherwise.
Preventive Care Is Already 0%, Deductible or Not
Certain preventive services carry 0% coinsurance by law from the first day of the plan year, before you’ve touched the deductible. Most health plans must cover recommended preventive care without any cost-sharing.5Office of the Law Revision Counsel. 42 USC 300gg-13 Coverage of Preventive Health Services This includes:
- Screenings rated “A” or “B” by the U.S. Preventive Services Task Force, such as blood pressure, cholesterol, diabetes, depression, and cancer screenings
- Immunizations recommended by the CDC’s Advisory Committee on Immunization Practices
- Pediatric preventive care under Health Resources and Services Administration guidelines, including well-child visits and developmental screenings
- Women’s preventive services covered under HRSA-supported guidelines
The protection applies only when the service is billed as preventive. A screening that turns up a problem can shift to diagnostic billing during the same visit, and standard cost-sharing then applies. A colonoscopy billed as a screening is free, but if a polyp is found and removed, some plans reclassify part of the visit as treatment. When possible, ask how the service will be coded before the appointment.
If Your Plan Is Grandfathered
Plans that qualified as “grandfathered” under the Affordable Care Act, meaning they existed before March 23, 2010, and have not made certain significant changes, are not required to cover preventive services at 0%.6eCFR. 45 CFR 147.140 – Preservation of Right to Maintain Existing Coverage Your Summary of Benefits will usually say so on the first page if it applies to you.