IFTA & IRP Explained: Fuel Tax and Registration for Interstate Truckers
If you cross state lines, you need IFTA and IRP. They're not optional. Here's what they are, how they work, and what happens if you skip them.
IFTA and IRP at a Glance
IFTA
International Fuel Tax AgreementWhat it does: Simplifies fuel tax reporting across states and provinces. Instead of buying fuel permits at every state border, you file one quarterly report.
Who needs it: Vehicles over 26,000 lbs GVWR (or with 3+ axles) that travel in two or more IFTA jurisdictions.
What you get: Two IFTA decals for your truck and an IFTA license.
IRP
International Registration PlanWhat it does: Lets you register your truck in one state (your base state) and legally operate in all IRP jurisdictions. Your registration fees are apportioned based on miles driven in each state.
Who needs it: Power units used in interstate commerce with a GVWR over 26,000 lbs (or with 3+ axles, or used in combination over 26,000 lbs).
What you get: A cab card showing your apportioned registration.
How IFTA Works
Every state charges a fuel tax. Without IFTA, you'd need to track every gallon purchased and every mile driven in each state, then file separate tax returns with all 48 states. IFTA lets you file one return.
Track Your Miles and Fuel
For each quarter, record: total miles driven in each state/province and total gallons purchased in each state/province.
Calculate Your Average MPG
Total miles driven / total gallons purchased = your fleet average MPG for the quarter.
Figure What You "Owe" Each State
Miles in State X / your average MPG = gallons "consumed" in State X. Multiply by that state's fuel tax rate = tax owed.
Subtract What You Already Paid
You paid fuel tax at the pump when you bought diesel in each state. Those purchases are credits against what you owe.
File One Return, Settle the Difference
If you bought more fuel in a state than your miles justify, you get a credit. If you drove more miles than your fuel purchases cover, you owe. Your base state collects and distributes.
Quick Example
You drove 5,000 miles in Idaho and bought 600 gallons there. You drove 3,000 miles in Montana but only bought 100 gallons there. Your average MPG is 6.5.
You overpaid in Idaho (bought more than consumed) and underpaid in Montana (drove more than your fuel purchases covered). IFTA handles the transfer.
IFTA Filing Deadlines
IFTA is filed quarterly. Miss a deadline and you owe penalties and interest.
How IRP Works
Without IRP, you'd need separate registration plates for every state you operate in. IRP lets you register once in your base state.
Choose Your Base State
Usually where your trucks are based, dispatched from, or where you have an established place of business.
List the States You'll Operate In
You select which jurisdictions to register for. You can add states later, but it costs extra mid-year.
Pay Apportioned Fees
Your registration fee is split among states based on the percentage of miles you drive in each. More miles in a state = more of your fee goes there.
Get Your Cab Card
You receive one plate and a cab card listing all jurisdictions. Keep the cab card in the truck — it's your proof of registration.
What IRP Costs
IRP registration typically costs $500 — $2,500/year per truck, depending on how many states you register for, the truck's weight, and the base state. First-year costs are often higher because you're registering in many states without prior mileage history (states assume even distribution).
8 IFTA & IRP Mistakes That Cost You Money
Not Keeping Fuel Receipts
You need receipts for every fuel purchase. No receipt = no credit. Digital/card statements aren't always enough for an audit. Keep receipts for 4 years.
Rounding Miles or Estimating
IFTA requires exact odometer readings for each trip. Estimating or rounding triggers audit flags. Record actual odometer at each state line crossing.
Forgetting to Add a State to Your IRP
If you drive in a state not on your cab card, you're operating without registration. That's a roadside violation with fines up to $500+ per state.
Filing IFTA Late
Even if you owe nothing (or are owed a refund), you must file on time. Late = penalties. Non-filing = license revocation.
Not Filing a Zero Return
If you didn't drive during a quarter, you still need to file a return showing zero miles and zero gallons. No filing = same as late filing.
Buying Fuel With Cash and Not Getting Receipts
Cash purchases without proper receipts can't be claimed as IFTA credits. Use a fuel card when possible — it creates an automatic record.
Not Displaying IFTA Decals
IFTA decals go on both sides of the cab, exterior, and must be visible. Missing decals = roadside fine ($50-$300+).
Ignoring Fuel Tax Rate Changes
Fuel tax rates change quarterly in many states. Using outdated rates means your filing is wrong. Use the IFTA rate chart published each quarter.
Who Doesn't Need IFTA or IRP?
Exempt from IFTA
- Vehicles under 26,000 lbs GVWR with 2 axles
- Recreational vehicles (not for hire)
- Government vehicles
- Vehicles operating only within one state
Exempt from IRP
- Vehicles with a GVWR under 26,000 lbs (with 2 axles)
- Buses used in transportation of personal property
- Government-owned vehicles
- Vehicles that never leave their base state
What Records to Keep (and for How Long)
IFTA requires you to retain records for 4 years from the filing due date. Here's what you need:
Per Trip
- Date of trip
- Origin and destination
- Route of travel
- Beginning and ending odometer readings
- Miles by state/province
- Vehicle unit number
Per Fuel Purchase
- Date of purchase
- Seller name and address
- Number of gallons
- Fuel type (diesel, gas, etc.)
- Price per gallon and total amount
- Vehicle unit number
Frequently Asked Questions
Can I do IFTA filing myself, or do I need a service?
Solo operators with one truck often file themselves — the math isn't complicated if you keep good records. Many ELDs generate reports that make filing straightforward. However, if you run multiple trucks or find the paperwork overwhelming, IFTA filing services typically charge $50-$150 per quarter. Some accountants who specialize in trucking include IFTA filing in their services.
What happens if I get audited?
IFTA audits typically cover 4 quarters. The auditor reviews your trip records, fuel receipts, and calculations. If your records are solid, audits are painless — maybe a small adjustment. If your records are poor or missing, the auditor will estimate your taxes owed (usually unfavorably) and you'll owe the difference plus penalties. Good records are your best defense.
Do I need IFTA for trips within my home state?
No. IFTA only applies to interstate travel. If you operate exclusively within one state, you don't need IFTA — you just pay that state's fuel tax at the pump. But the moment you cross a state line commercially, you need IFTA for all your operations (even the in-state miles get reported).
What's a trip permit, and when would I use one?
A trip permit is a temporary authorization to operate in a state not on your IRP cab card. They typically cost $15-$50 per state per trip and are valid for a single trip (usually 72 hours). Use them for one-off loads in states you don't normally travel. If you start going to a state regularly, add it to your IRP instead — trip permits add up fast.
Can I change my base state?
Yes, but it involves paperwork and timing. You'll need to cancel your registration in the old base state and re-register in the new one. Best done at renewal time to avoid duplicate fees. Some states require proof of a physical business presence (office, terminal, or established home) to be your base state.
Need Help Getting Set Up?
IFTA, IRP, insurance, BOC-3, UCR — new authority compliance has a lot of pieces. We help new trucking companies get everything in order so they can start hauling legally and stay that way.
Get a Free QuoteOr call (208) 557-1435