The Medicare 8-Minute Rule for Physical Therapy

Under Medicare's 8-minute rule, the timed minutes recorded during the visit decide how many units a clinic can bill.

Under the Medicare 8-minute rule, a clinic totals every timed minute in a Part B outpatient therapy visit and bills 15-minute units, with 8 or more minutes earning the final unit.

That sounds like simple arithmetic. It is not. A timed code is a CPT code billed in 15-minute units of one-on-one treatment, and the count depends on which minutes enter the pool and which payer receives the claim. Private payers may choose either counting method, even inside Medicare Advantage, so one visit can have two correct answers.

The line between timed and untimed services is also becoming a payment question. Larry Benz, who writes on physical therapy payment, reported in November 2025 that the final 2026 Medicare Physician Fee Schedule, released on October 31, 2025, carried a -2.5% "efficiency adjustment" to work RVUs for non-time-based services. APTA had flagged that very few PM&R codes are truly non-time based.

Why open a billing guide there? Because classification now drives both the unit count and the rate. Accurate classification = KEY, and it starts with knowing exactly which codes the rule covers.

What Is the Medicare 8-Minute Rule and Which Codes Does It Cover?

The Medicare 8-minute rule sets how many 15-minute units a clinic bills for timed CPT codes in a Part B outpatient therapy visit, based on the total timed minutes.

Count any visit in four steps:

1. Separate the timed codes from the untimed codes on the treatment note.
2. Add the minutes of every timed service into one total for the session.
3. Divide that total by 15 to find the full units.
4. Bill one more unit when 8 or more minutes remain, and no extra unit when 7 or fewer remain.

Start with what CMS actually requires before looking at where clinics get it wrong. The bar is 8 or more minutes. On its Therapy Services page, last modified on March 10, 2026, CMS calls that figure "the Medicare billing requirement for that final 15-minute service unit" and describes it as "more than half" of the unit. Why 8? Because it is the first whole minute past the halfway mark of a 15-minute unit. The detailed billing requirements sit in the Medicare Claims Processing Manual, Publication 100-04, Chapter 5, which local Medicare coding articles name as their source.

The scope is narrow, and precision here is KEY. The rule applies to Medicare Part B outpatient therapy, and only to timed CPT codes billed in 15-minute units. Common timed codes in a physical therapy note include:

• 97110: therapeutic exercise
• 97112: neuromuscular re-education
• 97140: manual therapy
• 97530: therapeutic activities

Untimed codes sit outside the rule. A physical therapy evaluation (97161, 97162 or 97163) or a re-evaluation (97164) is billed once per visit, however long it takes. Those minutes never enter the timed pool. Only one-on-one skilled treatment counts, so time spent documenting or attending to another patient stays out as well.

Once the pool is set, the unit count comes straight from the threshold chart.

Total timed minutes in the visit	Billable units
8 to 22 minutes	1 unit
23 to 37 minutes	2 units
38 to 52 minutes	3 units
53 to 67 minutes	4 units

Fewer than 8 timed minutes in the whole visit earns no unit at all.

Let's run one visit through the chart, and keep it in mind, because I return to it throughout this article. The therapist delivers 24 minutes of neuromuscular re-education (97112) and 23 minutes of therapeutic exercise (97110). The pool is 47 minutes, which lands in the 38 to 52 row: 3 units. You bill 2 units of 97112, the code with the most time, and 1 unit of 97110.

The common assumption is that each code gets tested against 8 minutes on its own. Medicare tests the visit total first. A comparison of 5 sources on this rule shows no disagreement about the 8-minute bar, yet they do not all explain pooling the same way. That gap is where a clinic's count starts to drift. For a biller, the visit is the thing being measured, not the code.

Unit counting is rule-bound, repeatable work, the sort of task I'd weigh first when a clinic reviews what to outsource in a medical practice. HelpSquad is a Clutch 2026 Top Medical Billing Company, so this article looks at the rule from the billing desk, not the treatment table.

One caution before moving on. Passing the 8-minute test does not clear a code for billing: Medicare's local coding article for outpatient therapy also warns that procedure codes may be subject to National Correct Coding Initiative (NCCI) edits, which should be checked before a claim goes out. The code list moves, too: for CY 2026, CMS added three remote therapeutic monitoring codes (98979, 98984 and 98985) and designated them "sometimes therapy," so confirm how any new code is designated before you count its minutes.

How Is the AMA Rule of Eights Different From Medicare's Method?

The AMA Rule of Eights, also called the Midpoint Rule, counts each timed code on its own. Minutes are never pooled, so totals can differ from Medicare's.

The pooled calculation is simple on its own. The trouble starts when a clinic's billing habits were formed on commercial claims that count time a different way.

Under the AMA method, each code stands alone. A 2021 Clinicient guide explained that a unit cannot be billed unless one-on-one treatment for that code lasted at least 8 minutes, and reported that AMA guidelines were accepted by most commercial and private payers. Nothing is added together.

Here is how the same notes count under each method.

Visit note	Medicare total-time count	AMA per-code count
24 minutes of 97112 plus 23 minutes of 97110 (the running visit)	3 units	4 units, 2 of each code
8 minutes of 97110 plus 8 minutes of 97140	1 unit, from 16 total minutes	2 units
10 minutes each of three timed codes	2 units	3 units
20 minutes of 97112 plus 20 minutes of 97110	3 units, from 40 total minutes	2 units

Look at the last row. Pooling is not always the stricter method. Medicare's count is lower in the first three rows and higher in the fourth, because two 5-minute remainders combine into a unit that neither code earns alone.

Which direction hurts? Both. Apply the per-code habit to a Medicare claim and the running visit carries one unit too many. Apply Medicare's pooling to a commercial claim that allows per-code counting and a unit goes unbilled.

So which payers use which method?

• Traditional Medicare, Tricare and Medicaid programs: total-time counting.
• Commercial, workers' compensation and auto insurers: generally per-code counting, though a few restrict it and some cap a visit at 4 units.
• Medicare Advantage and Medicaid managed care plans: either method. The plan chooses, and UnitedHealthcare is a notable private payer that follows total time.

Medicare Advantage is where I'd slow down. In a 2024 r/physicaltherapy thread, one therapist described managed Medicare Part B as "contract dependent," paid either on unit-based fee for service or at a flat per-visit rate, and added, "We keep a contract spreadsheet so that we can keep track." Another said the majority of Medicare Advantage plans followed AMA guidelines, not CMS.

A patient's Medicare card does not settle the method. The plan contract does.

A brief aside on vocabulary. Rule of Eights and 8-minute rule sound like the same thing, and I suspect that near-match confuses more billers than the arithmetic does. I'd write both names out in full in any billing policy.

Back to the contract. Someone has to keep the list of which plan follows which method, and it has to be in front of the person entering charges. If nobody in your clinic owns that reference, it is a sensible job to hand to a healthcare BPO services team.

That settles the method. It does not settle what a Medicare reviewer looks for once the method is right.

What Do Medicare Reviewers Flag on Timed Units, and How Do You Check a Claim First?

As a Clutch 2026 Top Virtual Assistant Company, HelpSquad's view is simple: reviewers flag billed units the documented minutes cannot support, so the reconciliation belongs before submission.

Two counting methods running in one clinic is the condition under which a wrong unit count stops being a slip and becomes a pattern. Why does that matter? Because a reviewer does not judge a pattern one claim at a time.

The federal evidence deserves a careful reading. In a report published in 2018, the HHS Office of Inspector General found that 61% of the outpatient physical therapy claims it reviewed did not comply with Medicare medical necessity, coding, or documentation requirements. The sample was 300 claims from July 1 through December 31, 2013. Of those, the 2018 report counted 184 that failed, with $12,741 in Medicare reimbursement claimed on them. From that sample, the auditors estimated that Medicare paid $367 million for non-compliant services during that 6-month period in 2013.

It's important to note what that audit was not. It was not a study of timed units alone, the dollar figure was a projection, and CMS generally disagreed with the findings. Still, the arithmetic is the warning. A small sample became a very large number. One counting habit, repeated on every visit, is not one error.

Pressure runs in the other direction, too. In a 2025 r/OccupationalTherapy thread, a therapist billing mostly Medicare Part B described being asked to change a 48-minute session to 38 minutes. The therapist refused. The director of rehab came back with this: "Please stay within the lowest range possible at the unit level to facilitate our business efficiency." The policy turned out to be "a verbal suggestion." One commenter was blunt: "Changing your numbers is fraud unless it was a mistake."

The minutes are the EVIDENCE. We have been founder-operated since 2015, and that shapes how I read the thread: a billing rule with no written owner is a risk, not a policy. So I would put four checks between the treatment note and the claim:

1. Confirm the payer's counting method from the contract, not from the patient's Medicare status.
2. Confirm every timed code carries its own minutes in the note, with untimed services left out of the pool.
3. Recount the units from the documented total and compare the result with what was billed.
4. Leave recorded minutes alone. If units and minutes disagree, correct the units and note why.

Who runs these checks matters less than whether they are written down. The same four apply when the work sits with an outside team under white-label back-office services, and the clinic still answers for the claim. Unit counts are not the only thing that sends a claim back. Medicare's local coding article for outpatient therapy states that a claim without a valid ICD-10-CM diagnosis code is returned to the provider as incomplete. And when an old pattern does surface? The OIG's recommendation described what a notified provider is expected to do: "exercise reasonable diligence to investigate and return any identified overpayments."

What Should a Therapy Clinic Do About the 8-Minute Rule Now?

Treat the 8-minute threshold as fixed and everything around it as moving: write down each payer's counting method, reconcile units to documented minutes before submission, and assign one owner.

The pressure on timed codes is not easing. In his November 2025 analysis, Larry Benz noted that CMS estimated a -1% impact for physical therapists in the proposed 2026 rule. A thinner margin leaves less room for unbilled units and none for refunds.

My view is plain. Which part of the billing workflow is fully within a clinic's own control? The handoff between the treatment note and the claim is, and over the next 6 to 12 months I expect payer methods, assistant-minute guidance and payment policy to keep shifting around a threshold that does not move.

So where do you begin? Pull one week of Medicare visits, recount the units from the recorded minutes, and see what each note can prove.