How often are health insurance denials overturned?

Insurers overturn roughly 44% of internal appeals, and independent external reviews overturn denials about half the time, according to KFF and federal data.

What percentage of denials get appealed?

Very few. KFF found that consumers appealed fewer than 1% of denied in-network claims in ACA marketplace plans.

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Do health insurance appeals actually work?

Short answer: far more often than people expect — and the people who appeal are a tiny minority.

<1%

of denied in-network marketplace claims are appealed

~44%

of internal appeals are overturned by insurers

~50%

of external reviews overturn the denial

Almost nobody appeals — that's the opportunity

In its analysis of ACA marketplace plans, KFF found insurers denied a meaningful share of in-network claims, yet consumers appealed fewer than 1% of those denials. The denial works because most people accept it.

When people do appeal, they win a lot

Among the denials that were appealed internally, insurers reversed themselves roughly 44% of the time. And when cases go to independent external review, the denial is overturned about half the time — with some state and study data trending higher in recent years.

Why appeals succeed

A denial is often a first-pass decision made against the insurer's own coverage criteria. A well-built appeal that (1) quotes those criteria, (2) shows you meet them with clinical evidence, and (3) invokes the right deadlines and rights forces a real second look. That's exactly what a strong appeal letter does.

The catch: you have to act in time

Appeals have deadlines — usually counted from the denial date. Miss it and the easy path closes. The single highest-value move is to start while the clock is on your side.

Put the odds to work

CareCost Appeals builds the evidence-backed letter most people never send — citing your insurer's own policy, real clinical evidence, and your state's rules.

Get started

Sources: KFF, Claims Denials and Appeals in ACA Marketplace Plans; U.S. Department of Health & Human Services / HealthCare.gov, external review; Health Affairs research on independent medical review outcomes. Figures are directional estimates from public data; see our methodology. Not legal or medical advice.