What Is Coinsurance?
Coinsurance is the percentage of covered healthcare costs you pay after meeting your annual deductible. Your insurance pays the rest. The most common split in the US is 80/20 โ your insurer covers 80%, you cover 20%.
The Exact Sequence: How Healthcare Costs Flow
Understanding coinsurance requires understanding the full payment sequence. Every covered medical expense flows through this order:
- Deductible phase: You pay 100% of covered costs until your annual deductible is met
- Coinsurance phase: After deductible, you pay your coinsurance % and insurance pays the rest
- Out-of-pocket maximum: Once you hit this cap, insurance pays 100% for the rest of the year
๐ก Coinsurance only applies in Phase 2 โ after your deductible and before your OOP max. Most people who see a doctor a few times a year never leave Phase 1.
A Real Example: $3,000 Specialist Bill
Plan: $2,000 deductible, 20% coinsurance, $6,000 OOP max. You've paid $500 toward your deductible this year.
- Remaining deductible: $1,500 โ you pay $1,500
- Remaining bill: $1,500 โ coinsurance applies
- Your coinsurance: 20% of $1,500 = $300
- Total you pay: $1,800 (out of the $3,000 bill)
Coinsurance vs Copay
These are two different cost-sharing methods your plan may use:
- Copay: A fixed dollar amount per visit ($30, $50). Predictable. Often applies to routine visits.
- Coinsurance: A percentage of the total cost. Scales with the size of the procedure. Often applies to larger services.
Some plans use only copays. Some use only coinsurance. Many use both โ copays for routine visits, coinsurance for hospital stays and procedures.
What Percentage Is "Good" Coinsurance?
Lower coinsurance (you paying less %) means more protection but higher premiums. Higher coinsurance (you paying more %) means lower premiums but more exposure when you need care.
- 10โ20% โ Common in Gold/Platinum plans. Good protection but higher premium.
- 20โ30% โ Common in Silver plans. Balanced trade-off.
- 30โ40% โ Common in Bronze plans. Lower premium, higher exposure.
Frequently Asked Questions
Does coinsurance apply to all services?
Not necessarily. Some services may have a copay instead of coinsurance, or may be fully covered with no cost-sharing (like preventive care under ACA rules). Your plan's Summary of Benefits lists cost-sharing for each service category.
Is there coinsurance for prescription drugs?
Many plans use both copays and coinsurance for drugs, depending on the tier. Tier 1 generics often use a flat copay. Tier 3 and 4 specialty drugs often use coinsurance, which can result in very high out-of-pocket costs for expensive medications.
What is the difference between coinsurance and copay after deductible?
Both are forms of cost-sharing that apply after your deductible is met. A copay is a fixed dollar amount per visit. Coinsurance is a percentage of the total claim. For a $1,000 procedure: a $40 copay is always $40; 20% coinsurance is $200. For a $100 visit: the copay is still $40, but coinsurance is only $20.