The 8-Minute Rule and More Physical Therapy Billing Unit Rules

Learn about the 8 minute-rule for physical therapy billing. Discover more physical therapy billing unit rates at Healthie.

Billing for physical therapy is generally based on the guidelines and reimbursement rates set by third-party payers. For patients who have Medicare, physical therapy billing is based around the 8-minute rule. Providers must provide a minimum of 8 minutes of a time-based physical therapy service in order to be able to bill for it. Many other insurance companies also adopted this rule and base their reimbursement off of it as well. 

Billing errors and mistakes can be costly and time consuming for physical therapy practices and it is important that you understand what the 8 minute rule is and how it relates to the physical therapy services that you provide. 

Below we discuss the basics that make up the 8-minute rule of physical therapy billing and dive into ways that will help you decrease your billing mistakes and increase your reimbursements.

Timed and Untimed CPT Codes 

Billing rules can be different depending on the type of insurance the patient has, but for Medicare and many insurances untimed and timed CPT codes are commonly addressed. 

For rehabilitation providers that bill Medicare, two different types of billing codes: untimed and timed codes are used. 

Untimed codes

Untimed codes are also known as service codes and include but are not limited to: physical therapy evaluation/re-evaluations, hot/cold packs, unattended e-stim. These codes can be billed once per treatment session and there is a predetermined rate for them, no matter the time spent on treatment.  

Timed codes 

Time codes include only skilled interventions and are reimbursed based on the time spent working 1:1 with their patient. Unlike untimed codes, timed codes can be billed multiple times per session. For billing purposes, technically, each timed code represents 15 minutes of treatment.  However, because treatment may not always be split into perfect 15 minute segments, the 8-Minute Rule was devised.  

The 8-Minute Rule for Physical Therapy Billing

In order to bill one unit of time for a code, the provider must spend at least 8 minutes performing the service. To calculate the number of units to bill for timed codes, add up the total minutes spent and divide by 15. This will give you the number of units you can bill.

So how do we calculate how many units to bill for?

Below is an easy to use 8-Minute Rule table that separates time spent on a physical therapy service and the associated number of units that could be billed:

8-22 mins: 1 unit

23-37 mins: 2 units

38-52 mins: 3 units

53-67 mins: 4 units

So for example, if you spent 15 minutes on therapeutic exercise and 15 minutes on gait training that would be a total  of 30mins or 2 units (1 unit of therapeutic exercise and 1 unit of gait training).

How to Deal with Remaining PT Minutes

According to CMS, if you perform two different timed services for 7 minutes or less but collectively they add up to 8 minutes or greater, then you can combine them together to bill for one unit. The service that was performed for the greater number of minutes would be the service that the unit would be billed under. 

For example:

If you perform 7 minutes of neuromuscular re-education and 5 minutes of therapeutic activity, together they equal 12 minutes in total. Therefore you could add them together and bill 1 unit under neuromuscular re-education (because that service was performed for a greater amount of time).

*It is important to note that some insurance companies do not allow for mixed remainders to be included in the billing. Physical therapists should check with the third party payer prior to billing if they have any questions or concerns in regards to this matter. 

Physical Therapy Billing Support through EHRs 

When working with physical therapy clients, it’s crucial to your workflows to leverage an EHR that has billing capabilities and support. Many modern EHRs integrate insurance billing features into their platform, so that providers can easily streamline the billing process, from charting to claim submission. As you begin the process of selecting an EHR to support your clinic, be sure to make a list of billing features that would be necessary for you. These may include:

  • Billing unit calculation
  • CMS-1500 form creation
  • Automatic submission to clearinghouse
  • Tracking of claims status within the EHR
  • Auto-complete CMS-1500 forms that pull information from chart notes

Choosing an EHR that is capable of supporting your insurance workflows can help streamline the entire billing process for your practice. It can combat the more difficult aspects of paper billing, while decreasing the overall time spent on the billing process. Digital billing through an EHR also allows providers to stay connected with their patients between treatment sessions.


Healthie offers a cloud-based EHR and telehealth platform that is fully integrated with billing and insurance features. You can quickly create Superbills and CMS 1500 claims, build packages, send invoices, and collect payments for out-of-pocket services. We have seen physical therapists and occupational therapists find success using Healthie to bill insurance within their practices. Whether you’re a solo practitioner or part of a multi-provider group or organization, our flexible membership plans adapt to meet your business needs. Let us help you launch your practice.

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