Physical therapy billing units calculator
The 8-minute rule is not per code — it is per day. Enter the direct one-to-one minutes against each timed CPT code and this works out how many 15-minute units the day actually supports, then shows you the units a code-by-code rounding would have invented.
Put today’s direct one-to-one minutes against each timed code. Pre-filled with a typical 45-minute visit.
- 971102 u alone
- 971401 u alone
- 975301 u alone
Total timed minutes
45
Units you may bill today
3
Rounding each code on its own would give 4 units. The day is capped at 3 by the total-minutes table, so 1 unit would be an overbill.
Units only. Whether the visit is payable at all is a separate question — see the $2,480 KX threshold below.
What the rule actually says
CMS words it in minutes, not in codes. “For any single timed CPT code in the same day measured in 15 minute units, providers bill a single 15-minute unit for treatment greater than or equal to 8 minutes through and including 22 minutes.” The table that follows runs to eight units, and the manual adds the line that does most of the work in an audit: when more than one timed code is performed in a day, the total number of minutes determines the number of units billed.
The mistake this tool exists to catch
Rounding each code separately and adding the results. Twenty-three minutes of 97110, thirteen of 97140 and nine of 97530 look like 2 + 1 + 1 = 4 units. The day is 45 minutes, which the table caps at 3. The fourth unit is an overbill.
The table, in full
| Total timed minutes | Units | What that looks like |
|---|---|---|
| 8–22 | 1 | A single modality, or two short ones that add to 8+ |
| 23–37 | 2 | A normal outpatient visit |
| 38–52 | 3 | A normal outpatient visit |
| 53–67 | 4 | A long or multi-discipline session |
| 68–82 | 5 | A long or multi-discipline session |
| 83–97 | 6 | A long or multi-discipline session |
| 98–112 | 7 | A long or multi-discipline session |
| 113–127 | 8 | A long or multi-discipline session |
Two short services that each miss the floor
The manual covers this explicitly. If two timed services are each 7 minutes or less but together reach 8 minutes or more, bill one unit — for the service performed for the most minutes. The same logic extends to three or more short services. It is not a rounding trick; it is that the day, not the code, is the unit of account.
Where the units stop mattering
Units decide what you may put on the claim. The annual threshold decides when you have to justify it. For 2026 the KX modifier threshold is $2,480 for physical therapy and speech-language pathology combined, and $2,480 for occupational therapy — up from $2,410 in 2025. Past that point the claim needs the KX modifier and documentation that the care is medically necessary; without it, it is denied. Targeted medical review starts at $3,000.
Red flag — refer out
None of this is a clinical judgement. If the reason a patient is racking up units is unexplained night pain, progressive neurological loss, unexplained weight loss or bowel and bladder change, stop counting minutes and refer.
Sources
- CMS Pub. 100-04, Medicare Claims Processing Manual, Chapter 5 §20.2.C — counting minutes for timed codes in 15-minute units · read 2026-09-04
- CMS Change Request 13437 — 2026 annual update to the per-beneficiary therapy thresholds · read 2026-09-04
- American Medical Association — Current Procedural Terminology (CPT) — CPT is an AMA trademark; the official descriptors are the AMA's and are paraphrased here, never reproduced · read 2026-09-04
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