The Complete 8-Minute Rule Guide for Therapy Providers

The 8-minute rule gets its name from a simple idea: a therapist must spend at least eight minutes providing direct, one-on-one treatment in order to bill Medicare for a time-based CPT code (also known as a constant attendance code).

To use the 8-minute rule correctly, it’s important to first understand the difference between service-based CPT codes (which are billed per session, no matter how long they take) and time-based CPT codes (which depend on how much direct treatment time you spend with the patient).

Table of Contents

• Why the 8-minute rule matters in ABA billing

• Service-based vs. time-based CPT codes

• How to apply the 8-minute therapy rule correctly

• Understanding the Medicare 8-minute rule chart

• Do documentation and supervision minutes count?

• How Cube Therapy Billing prevents costly 8-minute rule mistakes

Why the 8-minute Rule Matters in ABA Billing

Here’s the thing: ABA therapy sessions often mix multiple activities, direct intervention, parent training, supervision, and documentation. Each piece adds up. 

The 8-minute rule defines when those minutes turn into billable units. If you deliver at least eight minutes of a time-based service, you can bill one unit. Miss that threshold, and you lose the unit.

Inconsistent application of the 8-minute rule is one of the most common reasons claims get delayed or rejected. Payers, especially Medicare, expect precise math and airtight documentation.

That’s why tools like Cube Therapy Billing bake the logic into your workflow, automatically applying the 8-minute rules every time you submit a claim.

Read more about the impact of the 8-minute rule for ABA therapists

Service-Based vs. Time-Based CPT Codes

Not all codes follow the same billing logic.

Service-based codes (also called untimed codes) are billed once per session, regardless of how long they take.

They’re tied to a single event or task, like conducting an initial assessment or updating a treatment plan. Examples include:

• 97151: Behavior identification assessment

• 97155: Treatment plan modification

• 97168 CPT code description: Reassessment of adaptive behavior treatment

You only bill these once per day per patient.

Time-based codes, on the other hand, are billed in 15-minute increments. Each 15-minute block represents one billable unit, but only if you hit the 8-min therapy rule threshold.

Read More About ABA CPT Codes

Common time-based ABA codes:

• 97153: Adaptive behavior treatment (individual)

• 97154: Group adaptive behavior treatment

• 97156: Family adaptive behavior treatment guidance

This is where the 8-minute rule therapy really comes into play.

How to Apply the 8-minute Therapy Rule Correctly

The formula is simple once you get it. You total the minutes of all time-based codes for the day. Every full 15-minute block counts as one unit, and if you have eight or more leftover minutes, that counts as another unit.

To make it clearer, here’s the 8-minute rule chart (adapted for ABA use):

Minutes of Direct Therapy	Billable Units
8–22 minutes	1 unit
23–37 minutes	2 units
38–52 minutes	3 units
53–67 minutes	4 units
68–82 minutes	5 units
83–97 minutes	6 units

This Medicare 8-minute rule chart applies to any payer that follows Medicare’s standard. Private insurance companies often mirror it closely.

So, if you work 50 minutes directly with a client, you bill 3 units. Add another 10 minutes of parent training? You’ve hit 4 units under the rule of 8 billing.

Example: Calculating 8-minute Rule Units

Let’s break down a typical session:

• 25 minutes of 97153 (direct treatment)

• 15 minutes of 97155 (protocol modification)

• 10 minutes of 97156 (family guidance)

That’s 50 total minutes of direct therapy. According to the 8-minute rule cheat sheet, 50 minutes equals 3 units.

If you also completed a reassessment using the 97168 CPT code description, that’s a separate service-based code, billed once. Your total for the day: 4 units.

Understanding the Rule of 8 Billing

Now, the rule of the 8 ABA therapy model, also called the Rule of Eights, differs slightly. Instead of totaling all minutes, it treats each CPT code individually.

So if you provide:

• 10 minutes of 97153

• 10 minutes of 97155

Each exceeds the 8-minute threshold, so you can bill one unit for each code.

But if you do 25 minutes of 97153 and 6 minutes of 97155, you only bill for 97153, since 97155 didn’t meet the 8-min rule threshold.

ABA payers sometimes prefer one method over the other. Cube Therapy Billing’s automation workflow automatically identifies which rule applies based on payer configuration, avoiding human math errors.

Read more about the impact of the 8-minute rule

Do Documentation and Supervision Minutes Count?

Yes, but only when they’re part of active treatment. That means the client is present, and the activity directly supports therapy goals. Examples include:

• Reviewing behavior data while the client is in session

• Adjusting a protocol based on the client’s responses

• Explaining strategy changes to the parent or caregiver

If you’re writing notes after the client leaves or doing team admin work, that time doesn’t count toward your 8-minute rule units.

Cube Therapy Billing helps clarify what’s billable and what’s not by tagging each activity type automatically, so you never overbill by mistake.

Common Pitfalls with the 8-minute Rule ABA Approach

Here’s what tends to trip people up:

• Mixing service-based and time-based codes in the same session

• Rounding up incorrectly when time splits across multiple codes

• Forgetting to combine the remaining minutes before applying the chart

• Billing for documentation done outside of treatment time

Medicare audits often flag these patterns. According to CMS data, improper time documentation accounts for roughly 12% of all therapy billing denials annually. That’s a problem automation can easily solve.

How Cube Therapy Billing Solves It?

Cube Therapy Billing was built with compliance logic that automatically applies the 8-minute rules every time. It tracks time spent per code, merges partial minutes correctly, and alerts you when a code doesn’t meet the 8-min rule requirement.

It even provides an on-screen 8-minute rule cheat sheet during session entry, so your RBTs and BCBAs always see how many 8-minute rule units can be billed before submitting the claim.

No calculators. No guesswork. No underbilling.

Stay Compliant, Get Paid Faster

The 8-min therapy rule can feel tedious, but it’s what keeps your ABA practice compliant and your revenue steady. Cube Therapy Billing helps you:

• Apply the correct Medicare 8-minute rule chart automatically

• Document minutes clearly for payer audits

• Prevent denials caused by math or timing errors

• Protect every billable unit your team earns

See Cube Therapy Billing in action, schedule a call today, and simplify compliance for every ABA session.

FAQs

1. What is the 8-minute rule?

The 8-minute rule is a billing guideline used by Medicare and many private insurers to determine how many billable units a therapist can charge for time-based CPT codes (like those used in ABA, PT, OT, or speech therapy)

2. Does the 8-minute rule apply to all payers?

Most insurance companies follow the Medicare standard, but always verify. Cube Therapy Billing flags payer-specific exceptions automatically.

3. How do I calculate mixed codes under the rule of 8 billing?

Add up minutes across all time-based codes. Every full 15-minute block counts as one unit; any leftover 8+ minutes add one more.

4. Can I count parent training if it’s via telehealth?

Yes, as long as it’s synchronous, direct, and documented as active treatment, telehealth minutes follow the same 8-minute rule therapy standard.