How to Calculate Your Denial Rate (And What to Do When the Number Is Too High)

Most behavioral health practice owners know that some claims get denied. Very few know their actual denial rate. And even fewer know what to do with that number once they have it.

That gap matters. Denial rates in behavioral health run 15 to 25% nationally, compared to 5 to 10% across the rest of healthcare.¹ If you're anywhere near that range, you may be leaving thousands of dollars on the table every month. This post walks through the denial rate calculation formula, how to benchmark where you stand, and what to do once you have the number.

What Is a Claim Denial Rate?

Your claim denial rate is the percentage of submitted claims that payers reject and refuse to pay, at least initially. It's one of the most fundamental metrics in revenue cycle management because it's a leading indicator of billing health, not a lagging one.

It's worth separating denials from rejections. A rejection is returned before processing, usually because of a data error like a wrong member ID or missing field. A denial happens after the payer reviews the claim and decides not to pay. Both affect your revenue, but they point to different problems.

Behavioral health practices tend to face a structurally harder billing environment than other specialties. That's not a reflection on the practice. It's the nature of the field: more medical necessity scrutiny, more complex authorization requirements, and more payer variability. Understanding your clean claim rate alongside your denial rate gives you a fuller picture of where things are breaking down.

How to Calculate Your Denial Rate

The formula is straightforward:

Denial Rate = (Total Denied Claims / Total Claims Submitted) x 100

If your practice submitted 600 claims last month and 90 were denied, your denial rate is 15%.

That count-based calculation is a good starting point. But there's also a dollar-based version that's worth running alongside it:

Denial Rate (by dollars) = (Total $ Denied / Total $ Submitted) x 100

The dollar-based calculation matters when your claim values vary widely across service types. A group practice billing for both outpatient therapy sessions and psychological testing may have the same denial count as last quarter, but if the denied claims are concentrated in higher-value testing claims, the revenue impact looks very different.

Track your denial rate monthly or quarterly for meaningful trend data. And pay attention to the distinction between your initial denial rate (claims denied on first submission) and your overall denial rate (which includes appeals and resubmissions). Your initial rate is the more actionable number because it isolates preventable, pre-submission errors.

What's a Healthy Denial Rate for Behavioral Health Practices?

General healthcare sets the bar at 5 to 10%, with anything below 5% considered excellent.² Behavioral health is a different story.

The national average for behavioral health denial rates sits at 15 to 25%.¹ That's two to three times higher than the general healthcare benchmark. Practices managing billing in-house often run between 10 and 20%. Behavioral health billing specialists, by contrast, routinely achieve first-pass approval rates of 95 to 98%, translating to denial rates in the 2 to 5% range.³

You're not imagining it if your denial rate feels high. Behavioral health really is harder to bill. But "common" and "acceptable" aren't the same thing. A Minnesota outpatient clinic running at 18% may feel like it's operating within normal range for behavioral health. It is. But there's a clear path from 18% to under 5%, and the difference in monthly revenue is significant.

Rates above 10% typically point to upstream problems: eligibility verification gaps, coding inaccuracies, or documentation that doesn't hold up to payer review. Your denial tracking process, or lack of one, is usually where the story begins.

Why Behavioral Health Practices Face Higher Denial Rates

Four factors drive behavioral health denial rates higher than other specialties.

Medical necessity scrutiny. Mental health diagnoses involve clinical judgment, and payers review behavioral health claims more aggressively as a result. Progress notes need to clearly reflect current severity, not just where the client started. Documentation that describes a client's baseline from six months ago won't satisfy a payer reviewer looking for justification of ongoing care.

Authorization complexity. Programs like ARMHS, CTSS, EIDBI, and TCM all require prior authorization. Lapses, expired authorizations, and services rendered before approval is received are among the most common denial triggers for behavioral health practices. An ARMHS provider in Illinois can submit a claim that's clinically appropriate and still receive a "lack of medical necessity" denial because the documentation language didn't match what the payer's reviewers look for.

CPT and modifier nuance. Behavioral health has its own coding landscape. Mismatches between the time billed, the modality (individual versus group), and the complexity level are frequent denial causes. Staying current on CPT updates matters, but so does applying codes consistently across every claim.

Payer inconsistency. What one commercial plan approves, Medicaid may deny. Practices billing multiple payers need to understand each payer's specific requirements rather than applying a single standard across the board. This is where knowing your denial rate by payer becomes far more useful than knowing it in aggregate.

How to Reduce Your Denial Rate

Eighty-six percent of denials are potentially avoidable.⁴ The challenge is that most practices don't have systems to catch the problems before claims go out. Here's where to focus.

Verify eligibility before every session. Coverage lapses, plan changes, and wrong payer information are common and preventable. A quick verification check before the appointment is far cheaper than working a denial after the fact.

Break down your denial rate by payer and reason code. A 15% aggregate rate tells you there's a problem. Knowing that 60% of your denials come from one commercial plan for authorization issues tells you exactly where to focus. Segmentation turns a general problem into a solvable one.

Tighten your documentation. Progress notes need to reflect current clinical severity and justify why the client isn't ready to step down in care. This is especially important for long-term clients whose notes may accurately describe their history but not their present need.

Don't let denied claims sit. Sixty-five percent of denied claims are never corrected and resubmitted.⁵ Each denied claim costs an average of $25 to $30 to rework.⁵ That investment only pays off if someone actually works it. Systematic denial management means every denied claim gets reviewed, corrected, and resubmitted on a defined timeline.

Track your first-pass rate separately. This is your most actionable metric. It isolates pre-submission errors before payer behavior enters the picture. When you improve your first-pass rate, everything downstream gets easier.

Pairing denial rate data with your A/R aging report helps you see both how often claims are denied and how long they sit before they're resolved or written off.

Final Thoughts

Your denial rate is one of the most telling metrics in your revenue cycle. It's also one of the least-checked metrics for practice owners managing everything else at the same time.

The formula is simple. Getting the data takes some effort. But the number you find may well surprise you, and what you do with it can meaningfully change your monthly cash flow.

At BreezyBilling, we track denial rates as part of every client's monthly performance review. We look at it by payer, by reason code, and over time, because a single aggregate number rarely tells the full story. When something's off, we dig in.

If you'd like a clearer picture of how your billing is performing, denial rate included, we're happy to take a look. Reach out to learn more about our net collection rate benchmarking and denial management services.

Footnotes

1. Behavioral Health Billing KPIs To Track — Prosperity Behavioral Health, 2025

2. Claim Denial Rate: How To Calculate It and Reduce It — CCD Care, 2024

3. Outsource Mental Health Billing: The Complete 2026 Guide for Therapists — Elite Med Financials, 2026

4. 6 Keys to Addressing Denials in Your Medical Practice's Revenue Cycle — MGMA, 2024

5. The True Cost of a Denied Claim in Your PT Practice — WebPT, 2024