Calculate your coinsurance share of medical bills after meeting your deductible. See exactly how much you pay vs what insurance covers.
After you meet your health insurance deductible, coinsurance determines how medical costs are split between you and your insurer. A common arrangement is 80/20: the insurer pays 80% and you pay 20% of covered expenses until you reach your out-of-pocket maximum.
Coinsurance can add up quickly for expensive procedures. A $50,000 surgery with 20% coinsurance means you owe $10,000 on top of your deductible — unless your out-of-pocket maximum kicks in first. Understanding this interaction between deductible, coinsurance, and OOP max is essential for budgeting healthcare expenses.
This calculator shows your exact coinsurance responsibility for any medical bill, factoring in how much deductible you've already met and your out-of-pocket maximum. These are educational estimates only and are not actual insurance quotes. Whether you are a beginner or experienced professional, this free online tool provides instant, reliable results without manual computation. By automating the calculation, you save time and reduce the risk of costly errors in your planning and decision-making process.
Many patients are surprised by coinsurance charges because they assume insurance covers everything after the deductible. This calculator clearly breaks down your share versus the insurer's share, helping you budget for upcoming procedures and understand your true financial exposure. Having a precise figure at your fingertips empowers better planning and more confident decisions.
Remaining Deductible = Annual Deductible − Deductible Met Deductible Applied = min(Remaining Deductible, Bill Amount) Coinsurance Base = Bill Amount − Deductible Applied Your Coinsurance = Coinsurance Base × (Coinsurance % / 100) Total Patient Cost = min(Deductible Applied + Your Coinsurance, OOP Max − OOP Already Paid)
Result: Your cost: $4,000 | Insurance pays: $16,000
Deductible already met ($2,000/$2,000). Coinsurance on $20,000: you pay 20% = $4,000. OOP max is $8,000, you've paid $2,000, so $6,000 remains. Your $4,000 is under that limit. Insurance covers $16,000.
Coinsurance is the percentage-based cost-sharing that applies after your deductible. While the concept is simple, the math can be surprising. A $100,000 hospital stay with 20% coinsurance could leave you owing $20,000 before your OOP max intervenes. This is why the OOP max is the most important safety net in your plan.
ACA marketplace plans are categorized by actuarial value, which reflects the average cost-sharing. Bronze plans (60% actuarial value) typically have 40% coinsurance, while Platinum plans (90% value) may have 10% or even 0%. Higher-tier plans cost more monthly but dramatically reduce your per-service exposure.
If you anticipate expensive care (surgery, cancer treatment, childbirth), calculate your maximum possible annual cost: deductible + coinsurance up to OOP max. This worst-case number is what you should prepare for financially, regardless of the specific coinsurance rate.
No. A copay is a fixed dollar amount (e.g., $30 per visit) while coinsurance is a percentage of the bill. Coinsurance can vary widely based on the cost of service, whereas copays are predictable. Some plans use copays for office visits and coinsurance for hospital stays.
In an 80/20 plan, after you meet your deductible, the insurer pays 80% of covered costs and you pay 20%. For a $10,000 procedure, the insurer pays $8,000 and you pay $2,000 (assuming deductible is already met and you haven't hit your OOP max).
Yes. Both your deductible payments and coinsurance payments count toward your annual out-of-pocket maximum. Once you reach the OOP max, insurance covers 100% of covered services for the rest of the plan year.
Most employer plans use 20% coinsurance (80/20 split). ACA marketplace plans range from 0% (Platinum) to 40% (Bronze). High-deductible plans often have 10–20% coinsurance, while some plans use 30% for certain services or out-of-network care.
Some plans apply coinsurance instead of flat copays for prescriptions, especially specialty drugs. A specialty medication costing $5,000/month with 25% coinsurance means $1,250/month out of pocket until your OOP max is reached.
Your OOP max is the ceiling. If your total annual out-of-pocket spending (deductible + coinsurance + copays) reaches the OOP max, insurance pays 100% of remaining covered costs. For 2026, ACA OOP maximums are $9,200 individual / $18,400 family.