How to calculate your UCR fleet size, unit by unit
Your UCR fee depends on one number: how many vehicles you own or operate. Getting it right means testing each unit, picking the right counting period, and keeping the list that proves it.
UCR fleet size in numbers
Your UCR fleet size is the number of power units that qualify as commercial motor vehicles and that you operate, registered in your name or leased for more than 30 days. Count them from your latest MCS-150 (option A) or over the 12 months ending June 30 before the registration year (option B). Trailers never count.
Most carriers pay UCR off whatever number sits on their MCS-150, and for a stable fleet that is fine. But that number can be years old, it may include trucks you sold, and it can miss a pickup and trailer that crossed state lines.
This guide covers only the count: which units qualify, which counting option to use, how leases and owner-operators change it, what you may leave out, and the records that back it up. For the 2027 deadline and how to file, see our UCR renewal guide.
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Key takeaways
Count power units only
A unit counts when it is self-propelled, used on the highway in commerce, and qualifies as a commercial motor vehicle. Trailers never count.
The trailer can make the truck count
A pickup under 10,001 pounds counts once its combination with a trailer reaches 10,001 pounds in interstate use.
Two counting options
Use your latest MCS-150 (option A) or the 12 months ending June 30 before the registration year (option B). For 2027, that is July 1, 2025 to June 30, 2026.
Leases over 30 days count
A truck leased to you for more than 30 days counts in your fleet. Rentals and trip leases of 30 days or less do not.
IRP plates stay in
You may leave out trucks that haul property only within one state, but never a truck with apportioned IRP plates.
Keep the list
The UCR Agreement requires a list of all your vehicles and of any you subtracted, ready for a state audit.
In this articleContents
What counts toward your UCR fleet size?
A vehicle counts toward your UCR fleet size when it is a power unit, qualifies as a commercial motor vehicle, is used on the highway in commerce, and is yours for UCR purposes. Run each unit through four questions.
- Is it self-propelled? Only power units count. Trailers have not counted since 2010, so a fleet of 4 tractors and 12 trailers counts as 4.
- Is it a commercial motor vehicle? It is rated or weighs 10,001 pounds or more, alone or with its trailer; carries placarded hazardous materials at any weight; or is designed to carry more than 10 passengers, including the driver.
- Is it used on the highway in commerce? A vehicle used only off-road doesn't count. A truck with equipment mounted on it, such as a crane or a utility body, does: the equipment is its cargo.
- Is it yours? It counts if it is registered in your name and you operate it, or you control it under a long-term lease. Who holds the title doesn't decide it; the name on the registration does.
The weight test uses the whole combination. A one-ton pickup is not a commercial motor vehicle alone, but when the pickup, trailer, and load exceed 10,000 pounds and the combination runs interstate, the pickup counts. Our guide to ELD requirements by vehicle walks through the same combination math.
Count intrastate trucks at this stage too. The UCR Handbook has you start from your full fleet, interstate and intrastate, and only then apply the optional exclusions below.
Option A or option B: which count should you use?
Federal law lets you base the count on either of two numbers, and you choose one when you register.
- Option A: the commercial motor vehicles on the most recent MCS-150 you filed with FMCSA, or the MCSA-1 if that is the form you filed.
- Option B: the vehicles you owned, long-term leased, or operated during the 12 months ending June 30 before the registration year. For 2027, that is July 1, 2025 through June 30, 2026.
The two can differ because the MCS-150 is updated only every two years. Option A fits a fleet that hasn't changed since the last update. Option B fits a fleet that shrank, or an MCS-150 that still lists trucks you sold. Trucks you add or drop after you register don't change this year's fee; they show up in next year's count.
Two limits apply. A new carrier can't use option B to claim zero vehicles because it wasn't operating last year: the Handbook says it must use its latest MCSA-1. And every 2027 auto-renewal is filed with option A, using the power units on your current MCS-150.
That record may be stale this year. FMCSA has suspended enforcement of biennial updates due on or after June 1, 2026 while it moves registration to Motus, and ucr.gov now asks every motor carrier to declare all the commercial motor vehicles it operates in interstate commerce when it registers. Our MCS-150 biennial update guide covers updating the record.
| Vehicles counted | Bracket | 2027 fee |
|---|---|---|
| 0–2 | B1 | $55 |
| 3–5 | B2 | $167 |
| 6–20 | B3 | $333 |
| 21–100 | B4 | $1,163 |
| 101–1,000 | B5 | $5,548 |
| 1,001 and above | B6 | $54,165 |
How do leased trucks and owner-operators change the count?
A truck you operate under a lease of more than 30 days counts in your fleet, even though it is registered to someone else. A truck you run under a lease of 30 days or less, such as a rental or trip lease, does not.
So an owner-operator's truck leased on to your authority for a year counts in your fleet. The UCR Board's rule is that a vehicle counts in the fleet of every USDOT number it is operated under, unless that fleet runs it only under short-term leases.
- Owner-operator with its own authority, leased out full time: it still registers for UCR, but if it operates none of its own trucks, it pays the lowest bracket.
- A truck run under two USDOT numbers: it counts in both fleets. Each USDOT number registers and pays separately.
- Holding company that owns and leases trucks to its operating company: the operating company counts them; the holding company registers at the lowest bracket.
- Only rentals: a carrier whose only trucks are short-term rentals pays the lowest bracket.
Which vehicles can you leave out or add?
After the full count, the law lets motor carriers subtract one group and add another. Both are optional.
Leave out: intrastate property trucks
You may exclude trucks used only in intrastate transportation of property, waste, or recyclable material. Three limits apply:
- A truck with apportioned IRP plates can't be excluded, and states treat an IRP-plated vehicle as strongly presumed countable.
- Passenger vehicles can't be excluded, except intrastate school buses of a carrier primarily in intrastate school bus work.
- "Intrastate" is narrow for UCR. A truck is interstate if, even once that year, it crossed a state line or carried freight that started or will end in another state or country, such as a port container.
Add: smaller for-hire vehicles
A for-hire carrier may add vehicles that carry freight or passengers for pay but aren't commercial motor vehicles, such as cargo vans under 10,001 pounds. Including them can only keep your bracket the same or raise it.
Two narrower rules: trucks a foreign carrier didn't operate in the U.S. during the counting period are left out, and government-owned vehicles used by a government contractor aren't counted in the contractor's fleet.
Example: one fleet, two counts
Take a small carrier registering for 2027. Its last MCS-150, filed in early 2025, lists 7 power units. Here is how each unit tests for option B, July 1, 2025 to June 30, 2026.
| Unit | Counts in option B? | Why |
|---|---|---|
| 3 owned tractors, IRP plates | Yes: 3 | Registered to the carrier and operated all year |
| Tractor sold in April 2025 | No | Gone before July 1, 2025, though still on the MCS-150 |
| Owner-operator tractor on a 12-month lease | Yes: 1 | Lease longer than 30 days |
| Tractor rented for two weeks in December | No | Lease of 30 days or less |
| Dump truck hauling only in-state loads | Optional | Exclusively intrastate property, no IRP plates |
| One-ton pickup with gooseneck trailer, interstate | Yes: 1 | Combination over 10,000 pounds |
| Six trailers | No | Trailers never count |
Option B gives 5 with the dump truck excluded, bracket B2 at $167. Option A gives 7, bracket B3 at $333. Both are lawful counts; the difference is $166 a year, and option B only holds up if the carrier can document it.
Paying below the bracket your MCS-150 suggests is what the UCR Plan calls a retreat, and it is one thing state audits look for. The next section covers what to keep.
What records back up your UCR count?
The UCR Agreement requires every registrant to keep records that support what it reported, including a list of all its vehicles and of any it subtracted. A base state can ask for that list in a compliance audit, and it can ask you to reconcile a difference from your MCS-150.
- The option you used and the counting period
- Each unit's make, GVWR, VIN, plate and state, and whether it is owned, long-term leased, or rented
- Lease agreements with start and end dates
- For each excluded truck, why it ran only intrastate and proof it has no IRP plates
- Your MCS-150 at the time and the UCR receipt
UCR audits are mostly desk reviews. States must audit every retreat from the two highest brackets, and the program compares each carrier's IRP-plated vehicles with the bracket it paid. Audits for a registration year run until March 31 of the following year, so a 2027 count can be questioned into 2028.
A carrier that can't justify its bracket pays a one-time fee adjustment, and one that doesn't pay has its registration suspended. If you find you paid too little or too much, our guide to correcting a UCR filing covers both, and you can confirm the count you paid on with the UCR registration lookup.
How Simplex helps with your UCR count
We count your fleet, pick the option your records support, file UCR, and keep the vehicle list for audits.
UCR counted and filed
Our UCR registration and renewal service files each year's registration and pays the fee for the bracket your count supports.
An MCS-150 that matches
Option A and auto-renew read your MCS-150. Our trucking authority packages cover USDOT and MC filings and MCS-150 setup and updates.
Plates and permits in line
IRP-plated trucks always count. Our permits team handles IRP trip permits, fuel permits, and oversize permits alongside UCR.
Frequently asked questions
Do trailers count toward UCR fleet size?+
Does a leased owner-operator truck count in my UCR fleet?+
Can I pay UCR on fewer trucks than my MCS-150 shows?+
Do I have to update UCR when I add a truck during the year?+
Does a pickup truck count for UCR?+
Where this information comes from
The counting rules below come from the UCR statute and the UCR Plan's own documents, checked on October 20, 2026.
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1
49 U.S.C. 14504a — Unified carrier registration
Fees by fleet size, owned or operated under a long-term lease, the MCS-150 or June 30 counting options, and the intrastate exclusion.
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2
UCR Plan — UCR Agreement (February 2020)
Leases over 30 days count, 30 days or less don't, IRP-plated vehicles can't be excluded, and the vehicle list registrants must keep.
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3
UCR Plan — UCR Handbook
The five-step count, the CMV definition, combination weight, leases, multiple USDOT numbers, new carriers, exclusions, and audits.
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4
UCR Plan — Fee Brackets
2027 brackets and fees per entity.
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5
UCR Plan — Frequently Asked Questions
CMV definition and no supplemental filing for fleet changes during the year.
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6
UCR — National Registration System
2027 notice asking carriers to declare all interstate commercial motor vehicles while MCS-150 updates are suspended.
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7
UCR Plan — UCR Dispatch, October 2026
2027 auto-renewals use option A and the power units on the current MCS-150.
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8
UCR Plan — UCR Dispatch, September 2026
FMCSA's suspension of biennial update enforcement for updates due on or after June 1, 2026.
Written by
Simplex Group
Permits & Fuel Tax Team, Simplex Group
Reviewed for technical accuracy by a Simplex permitting manager before publication. Simplex has registered and filed permits and fuel taxes for interstate carriers across all 50 states for more than 20 years.
Published · Updated
Related articles and services
Pay UCR on the fleet you can prove
A UCR count is quick with a vehicle list in front of you: test each unit, compare option A with option B, apply any exclusion you can support, and file the list with your receipt. It can save a bracket, or an audit adjustment months later.
If you want us to run the count and file your UCR, talk to our team.