Home/Tools/Therapy Units Calculator

Free tool · PT, OT, SLP · CY2026

Therapy units calculator, running the real 8-minute rule.

Enter treatment minutes by CPT code and watch Medicare's timed-unit math build in front of you: the total timed minutes, the ladder rung they land on, how the units split across codes, which untimed codes bill separately, and what a PTA or OTA modifier does to the money. Every rule traces to a CMS document cited at the bottom of this page.

Start calculating → Get a therapy billing audit

First unit at

8 min

Then every

15 min

Untimed codes

1 unit

CQ / CO pays

85%

KX threshold

$2,480

Sources

cms.gov

Plain languageWhat the 8-minute rule actually says.

Medicare pays outpatient therapy in 15-minute units, but a therapist does not treat in tidy 15-minute blocks. The 8-minute rule is the bridge. Add every timed treatment minute in the visit, look the total up on one published ladder, and that is how many units the visit supports. Not per code. Per visit, on the total.

Floor

8 min

Below 8 total timed minutes, no timed unit is billable

Step

15 min

Each unit past the first needs another 15 minutes

Midpoint

8 of 15

More than half a unit earns the whole unit

Basis

Total

The ladder reads total timed minutes, never one code alone

THE LADDER 8 to 22 minutes = 1 unit. 23 to 37 = 2. 38 to 52 = 3. 53 to 67 = 4. 68 to 82 = 5. 83 to 97 = 6. Every unit after that needs 15 more minutes.

Two things go wrong constantly. First, billers run the ladder on each code separately, so a visit with 7 minutes of manual therapy and 7 minutes of therapeutic exercise gets billed as zero units when the 14-minute total actually supports one. Second, billers fold untimed minutes into the timed total, which inflates the unit count and turns an honest visit into an overpayment. The calculator below keeps those two pools strictly apart and shows you the arithmetic either way.

Ladder source: CMS Medicare Claims Processing Manual, Chapter 5, section 20.2 · clm104c05.pdf

The toolRun one visit through the whole rule.

Everything runs in your browser. Nothing you enter is stored or sent anywhere. Enter total treatment minutes per timed code, and if a PTA or OTA furnished part of that service, enter their minutes in the second box so the de minimis test and the CQ or CO modifier can be applied.

STEP 1

Discipline and scenario

Therapy discipline

CQ MODIFIER Physical therapy: services furnished in whole or in part by a physical therapist assistant carry the CQ modifier and pay at 85 percent of the otherwise applicable fee schedule amount.

STEP 2

Timed codes, in minutes

Timed CPT code

Total min

Of which PTA/OTA

Enter the total one-on-one treatment minutes for each code, including any minutes the assistant furnished. The second box is the assistant's share of that same number, so it can never exceed the total.

STEP 3

Untimed, service-based codes

1 UNIT EACH These are service-based codes. Each bills one unit per day regardless of duration, and their minutes never enter the timed total above. Mixing them into the timed minutes is the single most common outpatient therapy unit error.

Live result · Medicare 8-minute rule

Timed pool

0 total timed minutes
Ladder band: under 8

Untimed pool

0 service-based codes
Minutes counted: 0

THE TWO POOLS NEVER MIX Untimed minutes are excluded from the timed total by rule. Total line items on the claim: 0 units.

Unit allocation by code

Enter minutes above to see the allocation.

Payment illustration, timed units only

Allowed $per timed unit

$0Full-rate units plus CQ/CO units at 85 percent

No assistant modifier applied.

Why this is the answer

Enter treatment minutes to see the reasoning, step by step.

Educational estimate only. This tool applies the Medicare Part B 8-minute rule for outpatient therapy under the Physician Fee Schedule. It does not model the substantial-portion or rule-of-eights methodology some commercial payers use, therapy caps and KX attestation on a running annual total, NCCI procedure-to-procedure edits and modifier 59 or the X modifiers, group therapy, supervised modalities, institutional or SNF Part A billing, or your MAC's local coverage policy. The allowed amount is an illustrative figure you enter, not a fee schedule lookup. It is not reimbursement, coding, or legal advice.

The ladderTotal minutes in, units out.

One table decides the unit count for the entire visit. The rung highlighted below moves live with whatever you entered in the calculator. Nothing about which codes were delivered changes this step; that comes next, in allocation.

Read it this way

Each unit is earned at its midpoint, not its full length.

A unit is 15 minutes of work, so Medicare grants the unit once you pass its halfway mark, which is 8 minutes. That is why the first unit opens at 8 rather than 15, and why every band afterwards is 15 minutes wide: 8 to 22, then 23 to 37, then 38 to 52, and onward. If the total timed minutes are 7 or fewer, no timed unit is billable at all.

Source: CMS Medicare Claims Processing Manual, Chapter 5, section 20.2 · clm104c05.pdf

Worked exampleOne visit, every mechanic in play.

A physical therapy visit: 24 minutes of therapeutic exercise of which a PTA furnished 12, 23 minutes of neuromuscular re-education by the PT, 5 minutes of manual therapy by the PT, plus a re-evaluation and mechanical traction. Load it into the calculator with one click using the button in Step 1.

Code	What was delivered	Minutes	Units
97110	Therapeutic exercise. One whole 15-minute block, remainder 9 minutes. PTA furnished 12 of the 24 minutes	24	2
97112	Neuromuscular re-education. One whole 15-minute block, remainder 8 minutes	23	1
97140	Manual therapy. No whole block, remainder 5 minutes, loses the contest for the spare unit	5	0
Timed total	52 minutes lands in the 38 to 52 band, which pays 3 units	52	3
97164	PT re-evaluation. Untimed, one unit, minutes excluded from the 52	n/a	1
97012	Mechanical traction. Untimed, one unit, minutes excluded from the 52	n/a	1
Claim total	3 timed units plus 2 untimed units	52	5

The spare unit is the interesting part. After each code takes its whole 15-minute blocks, two units are spoken for and one is left over. Both 97110 and 97112 hold a remainder of 8 minutes or more, so both are eligible, and the larger remainder wins: 9 minutes on 97110 beats 8 on 97112. Manual therapy delivered 5 real minutes of care and earns nothing, because its remainder never reached the 8-minute midpoint and two better claims were ahead of it.

ASSISTANT The PTA furnished 12 of the 24 minutes on 97110, which is 50 percent, far above the 10 percent de minimis line. But the PT independently furnished 12 minutes, which clears the 8-minute midpoint of the final unit, so one of the two units is billed clean and only the other carries CQ.

That single distinction is worth real money at scale. At an illustrative $100 allowed per timed unit, the visit's three timed units pay $285 rather than $300, a 5 percent haircut on the visit. Get the final-unit exception wrong in the other direction, append CQ to both units, and you have given away another $15 that the fee schedule owed you. Multiply by a caseload.

De minimis standard, the 8-minute final-unit exception, and the 85 percent payment: CMS Therapy Services and the CQ/CO billing examples · cms.gov billing examples

AllocationWhich code gets the unit.

The ladder gives you a number of units for the visit. Allocation decides whose code they land on, and it runs in a fixed order. This is where audits are won and lost, because the units are defensible only if you can narrate the order.

Step	Rule	What it means at the desk
1	Total the timed minutes and read the ladder	The visit's unit count is fixed before any code is considered
2	Every whole 15 minutes on a code earns that code a unit	32 minutes of 97110 guarantees 2 units, with 2 minutes left over
3	Spare units go to the largest leftover, when the leftover is 8 or more	A 9-minute remainder beats an 8-minute remainder for the last unit
4	If no leftover reaches 8, the spare unit goes to the code with the most treatment time	20 minutes of 97110 plus 5 of 97140 is 2 units, both on 97110
5	On an exact tie, the treating therapist chooses	The clinician decides which service dominated the session, and documents it

The tie-break is a clinical decision

Do not let the billing system pick for you silently.

When two codes hold identical leftovers and only one unit remains, no arithmetic can separate them. The therapist who delivered the care chooses which code carries the unit and the note should say why. The calculator flags every tie it hits rather than resolving it quietly, because a system that picks a favourite code every time builds a billing pattern that an auditor can see from orbit.

CQ and COWhat an assistant does to the money.

When a physical therapist assistant or occupational therapy assistant furnishes part of a service, the line can carry a payment modifier and pay less. The test is arithmetic, and there is one exception that gives money back.

Modifier, PT

Service furnished in whole or in part by a PTA

Modifier, OT

Service furnished in whole or in part by an OTA

De minimis

10%

At 11 percent or more of the service, the modifier applies

Payment

85%

Of the otherwise applicable PFS amount, from Jan 1 2022

THE TEST Assistant minutes divided by total minutes for that service, times 100, rounded to the nearest whole number. Greater than 10 percent and the line carries CQ or CO.

The exception worth knowing

The therapist's own 8 minutes protect the final unit.

When the therapist and the assistant both work on the same service, the final 15-minute unit of the billing scenario is billed without CQ or CO if the therapist independently furnished 8 minutes or more of that final unit. The de minimis reduction does not reach a unit the therapist personally carried past the midpoint. Units the assistant furnished independently still carry the modifier and still pay at 85 percent.

The calculator implements exactly this: whole 15-minute blocks the therapist furnished alone are billed clean, one further unit is billed clean when the therapist's remaining minutes reach 8, and everything else on that code carries the modifier.

Sources: CMS Therapy Services · CQ/CO billing examples · MLN Matters MM12397 · CY2022 PFS final rule

CY2026 thresholdsThe number that stops the money.

Units are only half the story. Therapy services run against an annual per-beneficiary threshold, and once a patient crosses it every further claim needs a KX attestation or it denies. Note the grouping: physical therapy shares its threshold with speech-language pathology, and occupational therapy has its own.

Threshold	PT and SLP combined	OT	What it triggers
KX modifier threshold	$2,480	$2,480	Append KX and attest that services above the threshold are medically necessary and documented
Targeted medical review	$3,000	$3,000	Claims above this become eligible for targeted review, though review is not automatic

Watch the pairing

PT rides with SLP, not with OT.

A patient receiving both physical therapy and speech-language pathology burns one shared $2,480 allowance, so a talkative course of SLP can push a PT claim over the line without a single extra PT visit. Occupational therapy runs on a separate $2,480. Practices that track thresholds by department rather than by beneficiary find this out the expensive way, in a denial batch.

Source: APTA, Medicare therapy thresholds, CY2026. Figures verified July 2026 and consistent with the thresholds published on our speech and audiology billing pages.

ReferenceTimed or untimed, code by code.

The dividing line is not clinical importance, it is whether the code descriptor carries "each 15 minutes". Codes that do are timed and feed the ladder. Codes that do not are service-based and bill one unit per day.

Code	Service	Type	Units
97110	Therapeutic exercise	Timed, 15 minutes	Ladder
97112	Neuromuscular re-education	Timed, 15 minutes	Ladder
97116	Gait training	Timed, 15 minutes	Ladder
97140	Manual therapy techniques	Timed, 15 minutes	Ladder
97530	Therapeutic activities	Timed, 15 minutes	Ladder
97535	Self-care and home management training	Timed, 15 minutes	Ladder
97542	Wheelchair management	Timed, 15 minutes	Ladder
97760	Orthotic management and training	Timed, 15 minutes	Ladder
97161	PT evaluation, low complexity	Untimed, service-based	1 per day
97162	PT evaluation, moderate complexity	Untimed, service-based	1 per day
97163	PT evaluation, high complexity	Untimed, service-based	1 per day
97164	PT re-evaluation	Untimed, service-based	1 per day
97010	Hot or cold packs	Untimed, supervised modality	1 per day
97012	Mechanical traction	Untimed, supervised modality	1 per day
97014	Electrical stimulation, unattended	Untimed, supervised modality	1 per day

Medicare-specific

97014 is not a Medicare code.

ASHA's electrical stimulation coding guidance states that "Medicare providers must convert this 97014 to G0283," the HCPCS code for electrical stimulation other than wound, unattended. Bill 97014 to Medicare and you get a rejection, not a payment. The calculator flags it on the code itself. Payment status for the other supervised modalities varies by payer and by MAC policy, so verify locally before you rely on separate payment.

Source: ASHA, Electrical Stimulation Coding Guidance. Code descriptors are shortened plain-language labels, not verbatim CPT descriptors. CPT is a registered trademark of the American Medical Association.

SourcesEvery rule, traced.

No number on this page is estimated. Each one is read from a CMS document or a named professional association publication. Where a figure could not be verified, it was left off rather than approximated.

What it verifies	Source	Date
The 8-minute ladder: 8 to 22 = 1 unit, 23 to 37 = 2, 38 to 52 = 3, 53 to 67 = 4, 68 to 82 = 5, 83 to 97 = 6, then plus 15 minutes per unit, and the mixed-code allocation and remainder rules	CMS Medicare Claims Processing Manual, Chapter 5, Part B Outpatient Rehabilitation, section 20.2 · cms.gov	Current
CQ and CO modifiers, the 10 percent de minimis standard and its calculation, the 8-minute final-unit exception, and payment at 85 percent of the otherwise applicable PFS amount from January 1, 2022	CMS Therapy Services and Billing Examples Using CQ/CO Modifiers · cms.gov	Current
The same 85 percent reduction and de minimis policy as issued to providers	MLN Matters MM12397, Reduced Payment for PT and OT Services Furnished in Whole or in Part by PTAs and OTAs · cms.gov	2021
The rulemaking that revised the de minimis standard, effective January 1, 2022	CY2022 Physician Fee Schedule final rule, document 2021-23972 · federalregister.gov	Nov 2021
CY2026 KX modifier threshold of $2,480 for PT and SLP combined and $2,480 for OT, and the $3,000 targeted medical review threshold	APTA, Medicare therapy thresholds · apta.org	CY2026
Medicare requires G0283 in place of CPT 97014 for unattended electrical stimulation	ASHA, Electrical Stimulation Coding Guidance · asha.org	Current

Scope: Medicare Part B outpatient therapy under the Physician Fee Schedule. Out of scope by design: commercial substantial-portion and rule-of-eights methodologies, NCCI procedure-to-procedure edits and the 59 and X modifiers, group therapy and supervised modality payment status, running KX threshold accumulation, SNF and inpatient Part A billing, telehealth policy, and MAC local coverage determinations.

FAQTherapy units, answered.

What is the Medicare 8-minute rule?

It is how Medicare converts treatment time into billable units for timed therapy CPT codes. Add every timed minute delivered in the visit, then read the total against the CMS ladder: 8 to 22 minutes is 1 unit, 23 to 37 is 2, 38 to 52 is 3, 53 to 67 is 4, 68 to 82 is 5, 83 to 97 is 6, and each further unit needs another 15 minutes. Under 8 total timed minutes, no timed unit is billable. The ladder is published in the CMS Medicare Claims Processing Manual, Chapter 5, section 20.2.

How do I split units across two or more timed CPT codes?

Take the total unit count from the ladder first, then allocate. Each code earns a unit for every whole 15 minutes it holds. If units are still unassigned, they go to the codes with the largest leftover minutes, and a leftover of 8 minutes or more supports a unit on its own. If no leftover reaches 8, the remaining unit goes to the code with the most treatment time. When two codes tie, the treating therapist chooses which code carries the unit and documents the reasoning.

Do untimed codes count toward the 8-minute rule?

No, and this is the most common outpatient therapy billing error. Service-based codes such as the PT evaluations 97161, 97162 and 97163, the re-evaluation 97164, hot and cold packs 97010, mechanical traction 97012, and unattended electrical stimulation bill one unit each regardless of duration. Their minutes never enter the timed total. Folding evaluation time into treatment time inflates the timed unit count and creates an overpayment that a probe review will find.

When does the CQ or CO modifier apply and what does it pay?

CQ is appended to physical therapy services furnished in whole or in part by a physical therapist assistant, CO to occupational therapy services furnished in whole or in part by an occupational therapy assistant. Divide the assistant minutes by the total minutes of that service, multiply by 100 and round to the nearest whole number; at 11 percent or more the modifier applies. For dates of service on or after January 1, 2022, a line billed with CQ or CO pays 85 percent of the otherwise applicable Physician Fee Schedule amount.

Is there an exception to the CQ and CO de minimis standard?

Yes. When the therapist and the assistant both treat during the same service, the final 15-minute unit of the billing scenario is billed without CQ or CO if the therapist independently furnished 8 minutes or more of that final unit. The reduction does not reach a unit the therapist personally carried past the 15-minute midpoint. Units the assistant furnished independently still carry the modifier and still pay at 85 percent.

What is the 2026 KX modifier threshold for therapy services?

For calendar year 2026 the KX modifier threshold is $2,480 for physical therapy and speech-language pathology combined, and a separate $2,480 for occupational therapy. Past the threshold you append KX to attest that the services are medically necessary and supported by documentation. The targeted medical review threshold is $3,000 per discipline grouping. Both figures are published by APTA on its Medicare therapy thresholds page.

Does this calculator work for commercial payers?

Use it as the Medicare answer and then check the contract. Many commercial payers follow the AMA substantial-portion methodology, often called the rule of eights, which asks whether each individual code reached 8 minutes rather than pooling the visit total. The two methods disagree constantly, and the disagreement always shows up as a unit-count denial. If your payer mix is mixed, your billing rules engine needs both, not one.

Now run the same math on every visit you billed.

This calculator checks one visit. ASP-RCM's therapy billing practice audits the whole book: unit defects against the documented minutes, CQ and CO application, threshold tracking by beneficiary rather than by department, and the denials those errors already caused. First look is free.

Get a therapy billing audit See PT billing services