8-Minute Rule Calculator
Checked against the CMS Medicare Claims Processing Manual. Reviewed . See sources.
What is the 8-minute rule?
The 8-minute rule is how Medicare Part B counts billable units for 15-minute timed therapy codes. Add all direct timed minutes for the day: 8 to 22 minutes is 1 unit, 23 to 37 is 2 units, 38 to 52 is 3 units, and so on. Each service gets a unit for every full 15 minutes, and the remaining units go to the services with the most minutes left over.
How many units can I bill for this visit?
Enter the direct one-on-one minutes for each 15-minute timed code from one date of service. Leave untimed codes out. Use whole minutes; decimals are rounded down. This runs in your browser: nothing you type is sent or saved.
Load a CMS worked example:
Enter minutes to see both results.
What are the CMS unit ranges?
| Units | Total timed minutes |
|---|---|
| 1 unit | 8 through 22 minutes |
| 2 units | 23 through 37 minutes |
| 3 units | 38 through 52 minutes |
| 4 units | 53 through 67 minutes |
| 5 units | 68 through 82 minutes |
| 6 units | 83 through 97 minutes |
| 7 units | 98 through 112 minutes |
| 8 units | 113 through 127 minutes |
CMS says the pattern stays the same for treatment times beyond 2 hours. Fewer than 8 minutes in total is not billed.
How are the units split across codes?
CMS ties the total to the day's timed minutes, then assigns units to services. A service that ran at least 15 minutes is billed at least one unit, and one that ran at least 30 minutes at least two. It is not appropriate to count every minute toward one code if other services ran more than 15 minutes. Any units left over go to the service with the most minutes remaining.
Here are the five worked examples from the CMS manual. Use the example buttons above to load any of them into the calculator.
| Example | Timed minutes | Total | Units and billing |
|---|---|---|---|
| Example 1 | 24 min 97112, 23 min 97110 | 47 min, 3 units | 2 units of 97112 and 1 unit of 97110. The service that took the most time gets the extra unit. |
| Example 2 | 20 min 97112, 20 min 97110 | 40 min, 3 units | 2 units of one code and 1 unit of the other. Either may take the 2 units because the times are equal. |
| Example 3 | 33 min 97110, 7 min 97140 | 40 min, 3 units | 2 units of 97110 and 1 unit of 97140. After 30 minutes of 97110 (two full units), 97140 has more minutes left (7) than 97110 (3). |
| Example 4 | 18 min 97110, 13 min 97140, 10 min 97116, 8 min 97035 | 49 min, 3 units | 1 unit each of 97110, 97116 and 97140. The ultrasound (97035) is not billed because 49 minutes only allows 3 units, but it is still documented. |
| Example 5 | 7 min 97112, 7 min 97110, 7 min 97140 | 21 min, 1 unit | 1 unit total. The qualified professional selects one of the three codes, because each ran the same amount of time. |
Who does the 8-minute rule apply to?
The CMS rule is written for Medicare Part B outpatient rehabilitation services, the physical therapy, occupational therapy and speech-language pathology therapy codes that are defined in 15-minute units. ASHA adds that it applies only to 15-minute timed codes.
It does not govern untimed codes. CMS says an untimed code such as speech-language evaluation 92521 is reported as one unit no matter how many minutes were spent. Evaluations are therefore left out of the calculator. For the speech-language treatment codes, see our CPT 92507 guide, and for the OT code family see the occupational therapy codes guide.
How is the CPT midpoint rule different?
The CPT convention counts each code by itself: a unit is reached once more than half of the 15 minutes has elapsed. APTA notes that the CPT manual guidelines do not require adding total minutes across codes. Many commercial payers write their own policy, so the result can differ from Medicare's.
| Medicare 8-minute rule | CPT midpoint rule | |
|---|---|---|
| How minutes are counted | All timed minutes in the day are added, then the total sets the units. | Each code is counted on its own. |
| When a unit is earned | Total timed minutes reach 8, 23, 38, 53 and so on. | More than half of the 15 minutes has passed for that code, so 8 whole minutes. |
| Three services of 7 minutes | 21 minutes in total: 1 unit. | No code reaches 8 minutes: 0 units. |
| 18, 13, 10 and 8 minutes | 49 minutes in total: 3 units (CMS Example 4). | Each of the four reaches 8 minutes: 4 units. |
| Who uses it | Medicare Part B outpatient therapy. | Payers that follow the CPT convention. Contracts and payer policy decide. |
What should the session note show?
- Total timed minutes for the day, which is the number the CMS unit table uses. CMS states that the total number of timed minutes must be documented.
- Minutes for each timed service, so the units assigned to each code can be traced. CMS says per-service minutes are not required in the treatment note, but they make the unit split easy to defend and they are needed for payers that count code by code.
- Total treatment time, including minutes spent on untimed codes. CMS says total treatment minutes, including untimed services, are also documented.
- Services that were performed but not billed, such as the ultrasound in CMS Example 4. CMS says to still document them in the treatment note.
- More than start and stop times. ASHA notes that start and stop times alone may not be sufficient: the note should also show what was done and how the time was used.
Frequently Asked Questions
What is the 8-minute rule?
It is the Medicare Part B method for counting units of 15-minute timed therapy codes. You add the direct timed minutes for the day and look up the total in the CMS table: 8 to 22 minutes is 1 unit, 23 to 37 is 2 units, 38 to 52 is 3 units. Fewer than 8 minutes of timed service in a day is not billed.
How many minutes do I need for 2 units?
Under the CMS table, 23 minutes of total timed service reaches 2 units (23 through 37 minutes). 3 units starts at 38 minutes and 4 units at 53 minutes. Under the CPT midpoint rule, a single code needs 23 minutes for 2 units as well (15 minutes plus at least 8 more).
Which code gets the extra unit when time is split?
CMS assigns the extra units to the service with the most minutes left over after counting full 15-minute units. In CMS Example 3, 33 minutes of 97110 and 7 minutes of 97140 total 40 minutes (3 units): 97110 takes 2 units for its first 30 minutes, then 97140 (7 minutes left) beats 97110 (3 minutes left) for the third unit. When the leftovers are equal, CMS lets the qualified professional pick (Examples 2 and 5).
Does the 8-minute rule apply to untimed codes?
No. CMS says an untimed code is reported with 1 unit regardless of the minutes spent, and gives speech-language evaluation 92521 as its example. The rule counts only direct one-on-one minutes of 15-minute timed codes. Untimed minutes still go in the total treatment time you document.
Is the CPT midpoint rule the same as the 8-minute rule?
No. ASHA describes them as separate methodologies that should not be used interchangeably, even though they can give the same result. The midpoint rule counts each code on its own and awards a unit once more than half of the 15 minutes has passed. The Medicare rule pools all timed minutes first. See the comparison table above for two visits where they differ.
Do commercial payers use the 8-minute rule?
It depends on the payer. APTA says it is critical to review payer policy to learn whether the payer follows the Medicare 8-minute rule or allows a unit each time the midpoint is passed, and that a contract term, for example a different minimum for additional units, takes precedence. Check the payer's written policy and your contract.
What if two services each ran 7 minutes or less?
CMS says that if two timed services each ran 7 minutes or less and together reached 8 minutes or more, you bill one unit for the service performed for the most minutes. The same logic applies to three or more such services (CMS Example 5: three services of 7 minutes make 21 minutes, which is one unit).
What should the session note record for timed codes?
At minimum, the total number of timed minutes for the day, as CMS requires, and the total treatment time including untimed services. Recording minutes for each service as well makes the unit split traceable and supports payers that count code by code.
Related references
Sources
- CMS: Medicare Claims Processing Manual, Chapter 5, section 20.2 (Reporting of Service Units With HCPCS)
- APTA: Coding for Timed Codes
- ASHA: Understanding Timed and Untimed CPT Codes
Payer rules vary. This calculator shows the unit counts produced by the Medicare 8-minute rule and the CPT midpoint rule for the minutes you enter. It does not choose codes, apply modifiers, payer edits or contract terms, and it is general education, not billing, coding, or legal advice. Confirm with the payer and the official sources above before billing. Nothing you enter is sent or stored.
Draft the session note, with minutes recorded
WellNotes drafts your session note from what you type. You review and edit every note, and you choose the codes.