If you’re a physical therapist, occupational therapist, or speech-language pathologist, you’ve probably wrestled with Medicare’s 8-minute Rule more times than you’d like to admit.
At first glance, it sounds simple: spend at least eight minutes providing a therapy service, and you can bill one unit. Easy, right?
Not quite.
Between timed codes, untimed codes, remainders, modifiers, and payer-specific variations, the 8-minute Rule has tripped up countless therapy practices. One missed detail can cost you hundreds in denied claims—or worse, trigger a compliance audit.
So let’s unpack it all step by step and provide practical advice you can actually use.
What Is Medicare’s 8-Minute Rule?
The 8-minute Rule is a Medicare billing guideline for timed therapy services under Part B (outpatient therapy). It tells you how to convert total treatment minutes into billable units using 15-minute increments.
In simple terms:
If you spend at least 8 minutes providing a direct, one-on-one, skilled therapy service, you can bill one unit of that CPT code.
Each “unit” represents 15 minutes of treatment, but Medicare allows partial units once you hit that 8-minute threshold.
Let’s look at the official Medicare timetable:
| Total Timed Minutes (All Services Combined) | Billable 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 |
This is straight from the Medicare Claims Processing Manual (Chapter 5, Section 20.2) — the gold standard reference every therapist should bookmark.
Timed vs. Untimed Codes: Know the Difference Before You Bill
Not every CPT code follows the 8-minute Rule.
Some are timed, meaning you bill per 15-minute unit. Others are service-based (untimed) — you bill them once per session, no matter how long they take.
Here’s how to tell them apart:
| Type | Examples | Billing Basis |
| Timed codes | 97110 (Therapeutic Exercise), 97112 (Neuromuscular Re-ed), 97140 (Manual Therapy), 97530 (Therapeutic Activities) | Bill per 15-minute unit (8-minute Rule applies) |
| Untimed codes | 97161–97163 (PT Evaluation), 97014 (Electrical Stimulation – unattended), 97164 (Re-evaluation) | Bill once per session, regardless of duration |
The 8-minute Rule only applies to timed codes. Untimed codes are billed once per day, even if you spend 45 minutes on them.
How the 8-Minute Rule Works
The 8-minute Rule determines how many units you can bill for timed therapy services under Medicare Part B. It doesn’t care how many different CPT codes you use — it cares how much total time you spent providing one-on-one, skilled therapy.
Think of it as a math formula with three key steps:
- Add up all the timed minutes you spent.
- Match that total to Medicare’s unit table.
- Distribute those units to the codes that took the most time.
Let’s break this down with practical examples.
Step 1: Add Up All the Timed Minutes
First, list every timed CPT code you used during that session and note exactly how many minutes you spent on each.
Here’s an example:
| CPT Code | Description | Time Spent |
| 97110 | Therapeutic Exercise | 15 min |
| 97140 | Manual Therapy | 10 min |
| 97530 | Therapeutic Activities | 12 min |
Total Timed Minutes = 15 + 10 + 12 = 37 minutes
Step 2: Match the Total to Medicare’s Time Table
Now, take those 37 minutes and check them against the official Medicare 8-minute table:
| Total Timed Minutes | Billable 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 |
Your total (37 minutes) falls into the 23–37 range, which means you can bill 2 units total.
Step 3: Assign Units to Each Code
Now comes the part where most people mess up — how to split those two units between multiple codes.
The Rule is simple:
Assign one unit to the service that took the most time first, then use the remaining time for the next service.
In our example:
- 97110 (Therapeutic Exercise): 15 minutes
- 97530 (Therapeutic Activities): 12 minutes
- 97140 (Manual Therapy): 10 minutes
Since 97110 took the most time, it gets the first unit.
The remaining 22 minutes (12 + 10) qualify for the second unit.
Final Billing:
- 1 unit of 97110
- 1 unit of 97530 (or 97140 — whichever fits the treatment rationale better)
Step 4: Handle Leftover Minutes (The “Remainder” Rule)
Now, let’s say you had a slightly different scenario:
| Code | Minutes |
| 97110 | 20 |
| 97530 | 13 |
| Total | 33 minutes |
33 minutes also lands in the 23–37 range, so you get 2 units total.
But what if you had 38 total minutes?
Now you’ve entered the 38–52 range, which equals 3 units.
The secret is in the remainder:
- After billing whole 15-minute chunks, count the leftover minutes.
- If the remainder is 8 minutes or more, it’s billable as an extra unit.
- If it’s 7 or less, it’s not.
Example:
- 15 + 15 + 8 = 38 → 3 units
- 15 + 15 + 7 = 37 → 2 units only
That one minute can make a difference between getting paid for 2 units or 3.
Step 5: Only Count Skilled, Direct, One-on-One Time
This part is critical for compliance.
Only count direct, skilled, face-to-face time that involves active therapy intervention. Do not include:
- Rest breaks
- Setup or clean up
- Patient education outside of active treatment
- Documentation time
- Unsupervised exercise or unattended modalities
Example:
You spend 5 minutes setting up an exercise machine and 10 minutes actually supervising the patient.
→ Only the 10 minutes count toward the 8-minute Rule.
| Example With Multiple Codes and RemaindersLet’s do a more complex case.CodeMinutes97110 (Therapeutic Exercise)2297140 (Manual Therapy)797530 (Therapeutic Activities)9Total Timed Minutes3838 minutes = 3 units total.Now assign:1st unit → 97110 (longest time: 22 min)Remaining 16 minutes (7 + 9) → qualify for 2 more units combined.Final:97110 → 1 unit97140 → 1 unit97530 → 1 unitAltogether, 3 total units were billed correctly. |
What Happens if the Total Time Is Below 8 Minutes?
If your total timed minutes for the day (across all timed codes) is less than 8 minutes, you cannot bill for any timed unit.
Medicare expects at least 8 minutes of direct skilled intervention to justify one unit.
Example:
- 97110 = 5 minutes → No billable unit.
Medicare’s Golden Formula for Quick Calculations
If you want to remember this quickly during your day:
Total timed minutes ÷ 15 = Number of full units
If remainder ≥ 8 → Add 1 more unit
If remainder ≤ 7 → Don’t add
Example:
43 total minutes ÷ 15 = 2 full units (30 min), remainder = 13 → Bill 3 units.
41 minutes ÷ 15 = 2 full units, remainder = 11 → Still 3 units.
37 minutes ÷ 15 = 2 full units, remainder = 7 → Only 2 units.
How to Handle Leftover Minutes (The Remainder Rule)
Here’s where people slip up.
Let’s say you provided:
- 20 minutes of 97112 (Neuromuscular Re-education)
- 13 minutes of 97530 (Therapeutic Activities)
Total = 33 minutes.
33 minutes also falls in the 23–37 range, so you get 2 units total.
Now, here’s the Rule for leftovers:
- Add up all timed minutes.
- Subtract whole 15-minute chunks.
- If the remainder is 8 or more minutes, you can bill an extra unit.
- If it’s 7 or less, you can’t.
So if your total were 38 minutes (15 + 15 + 8), you’d qualify for three units.
Medicare says you can combine leftover minutes across different timed services, as long as the total remainder is ≥ 8.
Documentation: The Secret to Surviving Medicare Audits
Medicare won’t just take your word for it. They need proof.
Your documentation should clearly show:
- Start and stop times (or total timed minutes)
- Services performed (CPT code + description)
- Patient’s response and progress
- Functional goals related to each service
- Signatures of the treating provider
Example entry:
97110 – 15 min: TherEx for upper extremity strengthening using resistance bands.
97140 – 10 min: Manual therapy – soft tissue mobilization of right shoulder.
Total Timed: 25 min (2 units). Patient tolerated treatment well with improved mobility.
Never include setup, rest, or documentation time in your total. Only direct, skilled, face-to-face time counts.
The 8-Minute Rule vs AMA CPT Rule (They’re Not the Same)
A significant point of confusion: not all payers use the same time calculation method.
| Criteria | Medicare 8-Minute Rule | AMA CPT Midpoint Rule |
| What It Measures | Total combined time for all timed codes | Time spent per individual code |
| Billing Unit Threshold | ≥ 8 minutes of total remaining time | ≥ 8 minutes of each 15-minute code |
| Used By | Medicare Part B, some Medicare Advantage plans | Commercial insurers, Tricare, etc. |
So, if you’re billing Cigna, Aetna, or BCBS, check their provider manual first. Many private payers follow the AMA midpoint rule, not Medicare’s total-time method.
When the 8-Minute Rule Doesn’t Apply
- Untimed codes (evaluations, re-evaluations, group therapy)
- Concurrent therapy (multiple patients at once)
- Modalities without constant attendance
- Non-Medicare payers following the CPT midpoint method
- Facility-based services (like SNFs, home health), where different rules may apply
Special Modifiers You Must Know
Medicare requires therapy-specific modifiers for proper claim routing:
| Modifier | Used For |
| GP | Physical Therapy |
| GO | Occupational Therapy |
| GN | Speech Therapy |
| CQ | Services furnished in part or whole by a Physical Therapist Assistant (PTA) |
| CO | Services furnished in part or whole by an Occupational Therapy Assistant (OTA) |
If a therapy assistant provides part of the treatment, you must determine whether the therapist contributed enough to meet the 8-minute threshold for the final unit. If not, the CQ/CO modifier applies — and reimbursement may be slightly reduced.
Best Practices for Therapy Practices
Here’s how smart clinics stay compliant and efficient:
- Use digital timers or EMR auto-tracking for each session.
- Plan treatment blocks strategically — avoid finishing at 7 minutes.
- Train staff quarterly on Medicare updates and payer differences.
- Keep a cheat sheet (like the table above) visible near treatment stations.
- Document clearly: “timed” vs “untimed” sections separated in your notes.
- Audit 5 random charts per month to ensure your billed units match the minutes.
- Stay updated: CMS updates therapy billing rules annually in the Physician Fee Schedule.
Final Thoughts
Medicare’s 8-minute Rule might look like simple math, but it’s more like a billing equation with compliance consequences. One miscounted minute, one unchecked modifier, or one wrong code allocation — and you’re looking at delayed payments or audit flags.
Think of it this way:
“If it isn’t timed, it isn’t billable. If it isn’t documented, it didn’t happen.”
Stay sharp, stay consistent, and train your team to treat time as data — because in therapy billing, every minute truly counts.
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Schedule a free RCM review.
FAQ 1
Does the 8-minute rule apply to each CPT code separately?
No. Medicare applies the 8-minute rule to the total combined time of all timed therapy services, not per individual CPT code.
FAQ 2
Can leftover minutes from different CPT codes be combined?
Yes. Medicare allows combining leftover minutes across timed codes as long as the total remainder is 8 minutes or more.
FAQ 3
Does Medicare Advantage follow the 8-minute rule?
Not always. Some Medicare Advantage plans follow the AMA midpoint rule. Always verify payer-specific guidelines.
FAQ 4
What documentation is required to support 8-minute rule billing?
Clear total timed minutes, services performed, patient response, functional goals, and provider signature are required.
FAQ 5
What happens if therapy assistants provide part of the service?
Modifiers CQ (PTA) or CO (OTA) may apply, potentially reducing reimbursement if assistant time exceeds allowed thresholds.
