Medicare billing
8-Minute Rule Calculator
Enter the timed minutes for each CPT code in the session. We'll tell you how many 15-minute units are billable under the CMS 8-minute rule, including how remainder minutes are combined across codes.
How the 8-minute rule works
Under the CMS 8-minute rule (Medicare Claims Processing Manual, Pub. 100-04, Chapter 5, §20.2), a 15-minute timed CPT code is billable when at least 8 minutes of direct one-on-one treatment are provided. When multiple timed codes are used in a single treatment day, total minutes across all timed codes determine the total number of billable units:
- 0–7 minutes → 0 units
- 8–22 minutes → 1 unit
- 23–37 minutes → 2 units
- 38–52 minutes → 3 units
- 53–67 minutes → 4 units
- 68–82 minutes → 5 units
- 83–97 minutes → 6 units
- …and so on (add 15 minutes per unit; +1 unit once the combined remainder is ≥ 8 minutes)
Each code first receives its whole 15-minute blocks of base units. Any remaining units allowed by the combined total are allocated to the codes with the largest leftover minutes.
Source: CMS Pub 100-04, Chapter 5 (PDF). Rule interpretation last reviewed 2026-04.
Disclaimer: This calculator is a tool to help clinicians think through billing and is not a substitute for clinical or billing judgment. CMS guidance and payer rules evolve; verify results against your current payer manuals before submitting a claim.