The 8-Minute Rule Explained: Medicare Therapy Billing Units
How Medicare counts billable therapy units — the official CMS threshold chart, worked examples for single and mixed-service visits, and the mistakes that trip up billing most often.
01What the 8-Minute Rule Actually Is
The 8-minute rule is the method Medicare Part B uses to convert minutes of therapy into billable units for time-based CPT codes — things like therapeutic exercise, manual therapy, neuromuscular re-education, and gait training. Each unit represents roughly 15 minutes of one-on-one treatment, but a service doesn’t need to hit a full 15 minutes to count. It needs to reach at least 8 minutes — the midpoint of that block — before it’s billable at all. This is codified directly in the Medicare Claims Processing Manual, Chapter 5, Section 20.2, the primary source every therapy biller should have bookmarked.
This rule applies to timed codes only — untimed, service-based codes like most evaluations are billed once per visit regardless of duration. And once more than one timed service is involved, the rule is calculated per visit, not per code. That’s the part that trips people up most, covered in detail below.
02The 8-Minute Rule Threshold Table
This is the part most people are actually looking for — bookmark it.
| Total timed minutes | Billable units |
|---|---|
| 8–22 min | 1 unit |
| 23–37 min | 2 units |
| 38–52 min | 3 units |
| 53–67 min | 4 units |
| 68–82 min | 5 units |
| 83–97 min | 6 units |
| 98–112 min | 7 units |
| 113–127 min | 8 units |
Under 8 minutes of total timed treatment, nothing is billable — that time simply doesn’t clear the threshold.
03Worked Example: A Single Service
A patient receives 27 minutes of therapeutic exercise (CPT 97110), and nothing else timed that visit.
A patient receives 21 minutes of manual therapy (CPT 97140), and nothing else timed that visit.
Straightforward when it’s one service, straight off the table. Most of the confusion starts when a visit includes more than one timed code.
04Worked Example: Mixed Minutes Across Several Services
Same visit, but now the patient receives three different timed services:
Here’s the key point: you don’t apply the 8-minute rule to each code separately and add up the results. You add the total timed minutes for the whole visit first, then look up the total on the table. Those 2 units then get distributed across the codes performed — generally to whichever services have the most minutes, one unit at a time, until the visit’s total is used up. Here, that’s 1 unit to 97110 (18 min, the largest) and 1 unit to 97140 (10 min, next largest). 97112 (8 min) doesn’t get a unit this visit, even though 8 minutes alone would clear the threshold if it were the only service performed — the visit’s total unit count is capped by total time, not by summing each code’s individual threshold.
Treating each code as if it earns its own units independently, instead of pooling the minutes first. Real-world visits with more codes, tied minute counts, or unusual combinations can get more nuanced than this example — for anything borderline, confirm against the CMS Claims Processing Manual, Chapter 5 directly.
05Common Mistakes With the 8-Minute Rule
- Rounding up too early 21 minutes of a single service is still 1 unit, not 2 — you need to actually reach 23 minutes to cross into the second unit.
- Applying the rule to untimed codes Evaluations and other service-based codes are billed once per visit regardless of duration. Running them through the 8-minute table is a common but avoidable error.
- Billing each code separately instead of pooling minutes Mixed-service visits are calculated from the total timed minutes, not code-by-code.
- Assuming every payer follows Medicare’s version exactly Some private payers and state Medicaid programs use the same table; others use a different threshold system entirely.
- Forgetting the floor Any single timed service under 8 minutes isn’t billable on its own — it needs to reach 8 minutes itself, or be combined with other timed minutes from the same visit, to clear the threshold as a pooled total.
06The 8-Minute Rule vs. the “Rule of 8s”
Not every payer uses Medicare’s exact threshold table. Some private insurers use what’s often called the “Rule of 8s,” which calculates units slightly differently, particularly around how remainders are handled when multiple codes are involved. The practical difference usually shows up at the margins — visits with total minutes right at a threshold boundary can sometimes bill a different number of units depending on which system a payer uses.
Don’t assume a private payer follows CMS’s table just because your facility primarily bills Medicare. When in doubt, check that specific payer’s billing manual.
07The 8-Minute Rule: Quick Answers
Does the 8-minute rule apply to evaluations?
No. Evaluations and re-evaluations are untimed, service-based codes billed once per visit — the 8-minute rule only applies to timed treatment codes.
What happens exactly at 8 minutes?
Eight minutes is the minimum needed to bill one unit. A service timed at 7 minutes, with no other timed services that visit, isn’t billable; at 8 minutes, it is.
Does this apply to group or concurrent therapy?
Group and concurrent therapy have their own billing considerations beyond the 8-minute rule itself, including how credit is divided among patients. See our Concurrent Therapy Productivity Calculator for how minutes are handled when you’re treating more than one patient at a time.
Do all payers use this exact table?
No — this table reflects Medicare Part B’s standard. Many private payers and Medicaid programs follow it, but some use a different system. Confirm with each payer directly.
Can I bill 2 units for 22 minutes if I round up?
No. 22 minutes stays at 1 unit under this table; it takes 23 minutes to reach 2 units.
08The 8-Minute Rule: Key Takeaways
- The 8-minute rule converts timed therapy minutes into billable Medicare units.
- It applies to time-based CPT codes only, not untimed service-based codes like evaluations.
- A service needs at least 8 minutes to count as one billable unit.
- With multiple timed services in one visit, total minutes are pooled first, then looked up on the table.
- Units are then distributed to the codes with the most minutes — not summed per-code independently.
- Not every payer follows Medicare’s exact table — some use the Rule of 8s instead.
09Sources & References
Check your own numbers
Run your visit’s minutes through our Billing Units tool to get an instant, accurate unit count — and see the full threshold table applied automatically.
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