Key takeaways
- Medicare turns the total minutes of timed therapy codes in a visit into units: 8 to 22 minutes is 1 unit, 23 to 37 is 2, and each further 15 minutes adds one.
- The visit total sets the number of units. The units are then split across the codes.
- Untimed services, such as evaluations and group therapy, are billed once and are left out of the timed total.
- Some commercial payers use the AMA midpoint rule instead, which counts each code on its own. Check the payer.
What the 8-minute rule is
The 8-minute rule is how Medicare counts units for timed therapy codes, the codes billed in 15-minute units. It is set out in the Medicare Claims Processing Manual, Chapter 5, section 20.2, and it applies to physical, occupational and speech-language therapy.
When only one timed service is given in a day, it is not billed for less than 8 minutes. When more than one is given, the total minutes of all timed codes decide how many units can be billed for the visit.
8-minute rule chart
| Total timed minutes | Units |
|---|---|
| Under 8 | 0 |
| 8 to 22 | 1 |
| 23 to 37 | 2 |
| 38 to 52 | 3 |
| 53 to 67 | 4 |
| 68 to 82 | 5 |
| 83 to 97 | 6 |
| 98 to 112 | 7 |
| 113 to 127 | 8 |
The chart continues in steps of 15 minutes. Only direct treatment time counts toward the total.
How to split units across codes
- Add the minutes of all timed codes and read the number of units from the chart.
- Give each code one unit for every full 15 minutes it was performed.
- Give any units left to the codes with the most minutes left over.
| Visit | Total | Units | Billing |
|---|---|---|---|
| 97110 for 24 minutes, 97140 for 23 minutes | 47 | 3 | 97110 x 2, 97140 x 1 |
| 97110 for 33 minutes, 97140 for 7 minutes | 40 | 3 | 97110 x 2, 97140 x 1 |
| 97110, 97140 and 97530 for 7 minutes each | 21 | 1 | 1 unit on one code |
The last row is the mistake the rule exists to stop: three codes that each reached 7 minutes do not earn three units. The total of 21 minutes earns one.
Timed and untimed codes
Only timed codes count. Common timed codes include 97110 therapeutic exercise, 97112 neuromuscular re-education, 97116 gait training, 97140 manual therapy and 97530 therapeutic activities. Evaluations, group therapy (97150) and unattended electrical stimulation are untimed. They are billed once per visit, whatever their length, and their minutes stay out of the timed total.
Medicare rule vs AMA midpoint rule
Medicare and other federal payers use the total-minutes method above. Some commercial payers follow the AMA midpoint rule, which applies the 8-minute threshold to each code on its own.
| Visit | Medicare total-minutes rule | AMA midpoint rule |
|---|---|---|
| 10 minutes of 97140, 8 minutes of 97110 | 18 minutes: 1 unit | 2 units, one on each code |
Payers also write their own policies, so check each one before choosing a method.
8-minute rule calculator
Enter the direct treatment minutes for each timed code in one visit. The calculator shows the Medicare units, how to split them, and the per-code AMA result for comparison.
Evaluations, group therapy and other untimed services are not counted. Medicare and other federal payers use the total-minutes method. Check each commercial payer policy.
Common 8-minute rule mistakes
- Billing a unit for every code that reached 8 minutes. Under Medicare the visit total sets the limit.
- Counting untimed services in the timed total.
- Counting time that was not direct treatment.
- Using Medicare math for a payer that follows the AMA midpoint rule, or the reverse.
- Rounding up a single service under 8 minutes. It is not billed.
8-minute rule FAQ
What is the 8-minute rule?
The 8-minute rule is how Medicare counts units for timed therapy codes. The total minutes of all timed codes in a visit decide how many units can be billed: 8 to 22 minutes is 1 unit, 23 to 37 is 2, and each further 15 minutes adds one.
How many minutes is one unit in physical therapy?
A timed unit is 15 minutes, but one unit can be billed from 8 minutes. Under the Medicare rule, 8 to 22 total timed minutes support 1 unit, and 23 to 37 support 2.
Does the 8-minute rule apply to all payers?
Medicare and other federal payers use it. Some commercial payers follow the AMA midpoint rule, which counts each code on its own, and others write their own rules, so check each payer policy.
What is the difference between the 8-minute rule and the AMA rule of eights?
The 8-minute rule adds up the minutes of all timed codes and reads the units from one chart. The AMA rule of eights applies the 8-minute threshold to each code separately, so the same visit can support more units under it.