Coding · June 15, 2026 · 5 min read

CPT 90837 vs 90834: When to Bill Each

90834 and 90837 are the two most-billed individual psychotherapy codes, and the most common source of time-based coding mistakes. The rule is simple, but the audit risk is real.

The difference in one table

Bill by documented time, not by habit

Both codes are time-based, so the deciding factor is the documented face-to-face time of the session. If you spent 50 minutes, bill 90834. If you spent 55 minutes, bill 90837. Your note should state the session length clearly enough that an auditor can see why the code was chosen.

Why 90837 gets audited

Because 90837 reimburses more, payers track providers who bill it at unusually high rates. That doesn't mean you should avoid it, if your sessions genuinely run 53 minutes or more, 90837 is the correct code. It means the documentation has to support both the time and the medical necessity of a longer session. Defaulting to 90837 for 45-minute sessions is what triggers downcodes, denials, and recoupment.

Common mistakes that cause denials

• Billing 90837 when the note documents only ~45 minutes
• No session time recorded in the note at all
• Telehealth sessions missing the correct modifier or place-of-service code
• Billing the same code for every patient regardless of actual session length

How to get it right at scale

For a busy practice, the safeguard is catching time/code mismatches before submission. An AI behavioral health billing specialist aligns the billed code to the documented time and flags risky patterns, so you capture the revenue you earned on true 90837 sessions without inviting an audit. For a full list of codes, see our behavioral health CPT code guide.

This article is for general reference only. CPT codes and payer rules change, verify against current CPT guidance and your payer policies. CPT is a registered trademark of the American Medical Association.