Coinsurance Calculator
Work out your share of a medical bill after the deductible and up to the OOP max.
This is an estimate, not insurance advice. Your actual coverage needs, plan costs, and payouts depend on your policy, insurer, and personal situation.
How it works
Coinsurance is the percentage of a covered bill you keep paying after you've met your deductible. If your plan lists 20% coinsurance, the insurer covers 80% of costs past the deductible and you cover the remaining 20%.
The order matters. You pay the full bill up to whatever deductible you have left, and only the amount above that gets split by the coinsurance percentage. So on a $10,000 bill with $1,500 of deductible remaining and 20% coinsurance, you'd pay the $1,500 plus 20% of the other $8,500.
Your total is still capped by the out-of-pocket maximum. If the deductible-plus-coinsurance math would push you past that ceiling, the tool stops there — because that's the most the plan can make you pay for covered care in a year.
Frequently asked questions
Is coinsurance the same as a copay?
No. A copay is a flat dollar amount, like $30 for a visit. Coinsurance is a percentage of the bill, so it scales with cost — 20% of a $10,000 procedure is $2,000, while a copay would stay fixed regardless of the total.
Why does the deductible come first?
Most plans require you to meet the deductible before coinsurance kicks in. Until then you pay 100% of covered costs. That's why the calculator applies your remaining deductible fully, then splits only the amount above it by your coinsurance rate.
What if the bill is smaller than my deductible?
Then you pay the whole thing and coinsurance never applies. The plan only starts sharing costs once you've spent past the deductible, so small bills land entirely on you until that threshold is crossed.