What Is Coinsurance? Definition + Examples (2026)

Example: How It Works in Practice

Example: $2,000 deductible, 20% coinsurance, $3,000 outpatient procedure. Use the [medical bill analyzer](/medical-bill-analyzer) to check your own statement.

Worked example
Step	Amount (2026)
Total allowed amount	$3,000
Your deductible (unpaid portion)	$2,000
Remaining balance after deductible	$1,000
Your 20% coinsurance on $1,000	$200
Your total out-of-pocket for this claim	$2,200

Source: [HealthCare.gov coinsurance definition](https://www.healthcare.gov/glossary/co-insurance/). Amounts illustrative.

Coinsurance vs. Copay: Key Differences

A copay is a fixed dollar amount at the time of service, often before the deductible. Coinsurance is a percentage applied after the deductible. Both count toward your out-of-pocket maximum. See Medicare eligibility if you are near age 65: Original Medicare charges 20% Part B coinsurance, not copays.

Coinsurance vs. Copay: 2026 comparison chart
Feature	Coinsurance	Copay
Amount type	Percentage of bill	Fixed dollar
When it applies	After deductible	Often before or after deductible
Counts toward OOP max?	Yes	Usually yes
Medicare Part B (2026)	20% standard rate	Not used for Part B services

Source: CMS 2026 Medicare Parts A and B Premiums and Deductibles (cms.gov).

Source: https://www.cms.gov/newsroom/fact-sheets/2026-medicare-parts-b-premiums-deductibles

Frequently Asked Questions

What is the standard coinsurance rate in 2026?

Medicare Part B uses a 20% standard coinsurance rate in 2026, meaning you pay 20% of the approved amount for most outpatient services after the $283 annual deductible. ACA marketplace plans vary: Bronze plans often have higher coinsurance (40-50%), while Silver and Gold plans typically range from 10-30%. Your plan's Summary of Benefits and Coverage lists the exact rate for each service category.

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

Yes. In 2026, all coinsurance payments for in-network covered services count toward your plan's out-of-pocket maximum. For ACA marketplace plans, the 2026 cap is $10,600 for an individual and $21,200 for a family. Once you reach that limit, your insurer pays 100% of covered in-network costs for the rest of the plan year.

How is coinsurance different from a deductible?

A deductible is the fixed dollar amount you pay before coinsurance kicks in. Coinsurance is the percentage split that applies after the deductible is satisfied. For example, with a $1,500 deductible and 20% coinsurance: you pay the first $1,500 in full, then 20% of each subsequent covered bill until you reach your out-of-pocket maximum.

Sources & References

1. HealthCare.gov - Coinsurance Glossary — Official ACA definition of coinsurance.

2. CMS - 2026 Medicare Parts A and B Premiums and Deductibles — Official 2026 Medicare Part B 20% coinsurance rate and $283 deductible.

3. CMS - 2026 ACA Out-of-Pocket Maximum — CMS 2026 cost-sharing parameters including OOP cap of $10,600 individual.

What Is Coinsurance?