What Is Coinsurance?

Coinsurance is your percentage share

Coinsurance is the percentage of a covered medical bill you pay after you have met your deductible. If your plan has 20% coinsurance, the plan pays 80% of covered costs and you pay 20% — until you reach your out-of-pocket maximum, after which the plan pays 100%.

Because it is a percentage rather than a flat amount, coinsurance on an expensive service can add up quickly. Twenty percent of a $2,000 MRI is $400; twenty percent of a $60,000 surgery is $12,000 — which is exactly why the out-of-pocket maximum exists as a backstop.

Coinsurance vs copay

A copay is a fixed dollar amount for a specific service — say $30 for a doctor visit — that you often pay even before meeting the deductible. Coinsurance is a percentage that usually applies after the deductible. Many plans use both: copays for routine visits and coinsurance for larger services.

When comparing plans, look at how each handles the care you actually use. A plan with low copays for primary care may still leave you with high coinsurance on a hospital stay, so the right choice depends on your expected pattern of care.

Frequently asked questions

Is a lower coinsurance always better?

Lower coinsurance means the plan pays more of each bill, but such plans usually carry higher premiums. Weigh it against how much care you expect to use.

Does coinsurance count toward my out-of-pocket maximum?

Yes. Coinsurance, copays, and the deductible all count toward your out-of-pocket maximum for covered in-network care.