Medicare’s 8-minute rule: how timed PT units work
For Medicare Part B outpatient therapy, the total minutes of timed treatment determine the maximum number of 15-minute units, with additional code-allocation rules when several timed services are performed.
Thresholds for total timed treatment
8–22 minutes
Generally supports one unit of timed therapy.
23–37 minutes
Generally supports two units.
38–52 minutes
Generally supports three units.
53–67 minutes
Generally supports four units. These ranges address total timed minutes, not a promise that any particular code allocation is correct.
Examples that trip up documentation
Example: 32 minutes across four treatments
Four separate eight-minute interventions do not equal four billable units. CMS illustrates that 32 total timed minutes supports two units, subject to the rules for selecting which codes to report.
Untimed services
Do not add time spent on an untimed service to the total timed-code minutes.
Multiple timed codes
The total-minutes threshold is only the first check. Selection of which code receives the units must follow CMS’s allocation guidance and actual services delivered.
Before signing
Check recorded minutes
Make sure treatment time is accurate and distinguishes timed from untimed activities.
Reconcile minutes and units
Flag a potential mismatch, then have the responsible clinician or billing professional verify the appropriate codes and units.
Consider payer rules
The examples here describe Medicare Part B guidance. Private insurers and other payers may have different conventions.
Frequently asked questions
Can I bill one timed unit for seven minutes?
Generally no when that is the only 15-minute timed service: CMS requires at least eight minutes.
If four exercises each take eight minutes, can I bill four units?
No. CMS specifically explains that 32 total timed minutes generally supports two units, not four.
Verify against current CMS guidance
Educational summary only. Review the current Medicare manuals, applicable Medicare Administrative Contractor rules, and payer-specific policies. No article substitutes for clinical or billing advice.
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