Denial rate in medical billing is the percentage of submitted claims that a payer denies. To calculate it, divide the number of denied claims by the total number of claims submitted in the same period, then multiply by 100. A practice that submits 1,000 claims in a month and has 50 denied has a denial rate of 5 percent.
Two versions of the number are worth tracking. The initial denial rate counts every claim denied on first submission, including those later paid on appeal. The final denial rate, sometimes called the write-off rate, counts only the claims that are never paid. A high initial rate with a low final rate points to costly rework. A high final rate means revenue is being lost.
Many billing teams aim to keep the initial denial rate under 5 percent. Practices often run higher because of coding errors, missing documentation, eligibility problems, or absent prior authorization. The overall rate hides most of the story, so break it down by payer, CPT code, provider, and denial reason code. A single payer or a single code often accounts for a large share of denials, and that is where fixing the process pays off first.
Denial rate pairs naturally with clean claim rate, since clean claims are the ones least likely to be denied. The most common causes and fixes are listed in Common Denial Codes in Billing + How to Fix Them, and denial management covers how to work the claims that are already denied.