What percentage of insurance appeals are successful?

Roughly 44% of internal appeals succeed on ACA marketplace plans, independent external reviews side with patients 40-50% of the time, and over 80% of appealed Medicare Advantage denials are eventually overturned.

Why do so few people appeal denied claims?

Under 1% of denials are appealed — people don't know they can, don't understand the denial code, or miss the deadline. All three are fixable, which is exactly what a decoder plus deadline tracking exists to do.

The numbers insurers hope you never see

Appeal win rates, by the numbers.

Fewer than 1 in 100 denied claims are ever appealed — yet when people do appeal, they win far more often than they lose at the higher rungs. Every figure below is from government or independent data, linked at the bottom.

The sourced numbers

~20% of in-network claims are denied on HealthCare.gov plans (KFF, 2023–24 — roughly 85 million denials a year).
Under 1% of denied claims are appealed (KFF). This silence is the insurers' business model.
~44% of internal appeals succeed on marketplace plans (KFF).
40–50% of independent external reviews side with the patient; New York's overturn rate rose from 38% to 53% (2019–2025, JAMA).
80%+ of appealed Medicare Advantage denials are eventually overturned (KFF / AMA).
95% of appealed skilled-nursing prior-authorization denials by the largest MA plans were overturned (HHS Office of Inspector General, 2026).

As AppealClock grows, this page will also publish live, anonymized win rates by denial code and insurer from appeals tracked in the tool — the transparency layer this industry has never had. No personal information is ever collected or published.

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Common questions

What percentage of insurance appeals are successful?: Roughly 44% of internal appeals succeed on ACA marketplace plans, independent external reviews side with patients 40-50% of the time, and over 80% of appealed Medicare Advantage denials are eventually overturned.
Why do so few people appeal denied claims?: Under 1% of denials are appealed — people don't know they can, don't understand the denial code, or miss the deadline. All three are fixable, which is exactly what a decoder plus deadline tracking exists to do.