How to File IFTA Quarterly: Step-by-Step Tutorial

Why Quarterly Filing Matters

Learning how to file IFTA correctly each quarter is one of the most important compliance responsibilities for any interstate trucking operation. The International Fuel Tax Agreement requires carriers operating qualified motor vehicles across state lines to report miles traveled and fuel purchased in every jurisdiction, then settle the difference in fuel taxes owed or credited. IFTA quarterly filing is not optional: even if your trucks sat idle all quarter, you must still submit a zero return to remain in good standing.

The consequences of late or inaccurate filings are severe. Penalties start at $50 or 10% of your net tax liability, whichever is greater, and interest accrues on any unpaid balance from the due date. Repeated violations can trigger an audit, and persistent non-compliance can lead to the revocation of your IFTA license, meaning your vehicles cannot legally operate across state lines. Beyond the financial penalties, an IFTA license revocation effectively shuts down your interstate operations until you reinstate it, a process that can take weeks.

This step-by-step tutorial walks you through the entire IFTA quarterly filing process, from gathering records to submitting your return. If you want a broader overview of how the IFTA program works, start with our complete IFTA reporting guide.

Prerequisites for Filing

Before you can file an IFTA return, you need three things in place:

• IFTA License: Issued by your base jurisdiction (the state or province where your vehicles are registered or where you have an established place of business). You apply through your state's department of transportation or motor carrier division. The license covers your entire fleet.
• IFTA Decals: Each qualifying vehicle must display two IFTA decals, one on each side of the cab exterior. Decals are issued with your license and renewed annually, typically by December 31st. Operating without valid decals can result in fines at weigh stations and roadside inspections.
• Base Jurisdiction: This is the state through which you file all of your IFTA returns. Your base jurisdiction collects the taxes and redistributes them to the other states and provinces where your trucks operated. All filings, payments, and credits flow through this single jurisdiction.

With these prerequisites in place, you are ready to begin the quarterly filing process.

Step 1: Gather Mileage Records

Accurate mileage records are the foundation of your IFTA return. You need to know exactly how many miles each qualified vehicle in your fleet traveled in each state and province during the quarter.

Acceptable mileage records include:

• Telematics/GPS data: The most accurate method. Providers like Motive and Samsara automatically log state-line crossings and calculate miles by jurisdiction.
• Trip sheets or driver logs: Manual records showing origin, destination, route, and odometer readings for each trip.
• Hub odometer readings: Odometer readings at the start and end of each trip, cross-referenced with the route taken.

For each vehicle, your records should show the total miles driven during the quarter broken down by every state or province entered. This includes loaded miles, empty (deadhead) miles, and any personal conveyance miles driven in a qualified vehicle. Do not exclude any miles; IFTA requires reporting of all miles operated in qualified vehicles.

If you are tracking mileage manually, use a state mileage guide or PC Miler to determine the miles allocated to each jurisdiction for a given route. However, manual tracking is error-prone. A single missed state border crossing can throw off your entire return.

Step 2: Compile Fuel Purchase Records

Next, gather all fuel purchase documentation for the quarter. You need to know the total gallons of fuel purchased and the state or province where each purchase occurred. Acceptable records include:

• Fuel card statements: Most fleet fuel cards (EFS, Comdata, WEX, Pilot RBI) provide detailed monthly or quarterly reports showing date, location, gallons, price per gallon, and total cost for each transaction.
• Fuel receipts: Paper or digital receipts from fuel stops. Each receipt must show the date, seller name and address, number of gallons, fuel type (diesel or gasoline), price per gallon or total amount, and the vehicle unit number or license plate.
• Bulk fuel purchase records: If you fuel from your own tanks, maintain records of bulk purchases and allocate gallons to individual vehicles based on fueling logs.

Organize purchases by jurisdiction. You will need the total gallons purchased in each state to calculate whether you owe additional tax or are due a credit for that state. Keep in mind that IFTA requires you to retain all fuel records for at least four years in case of an audit.

Step 3: Calculate Total Miles by Jurisdiction

With your mileage records assembled, sum the total miles driven by your entire fleet in each jurisdiction during the quarter. Create a spreadsheet or table with one row per state/province and a column for total fleet miles in that jurisdiction.

For example, if you have three trucks and Truck A drove 4,200 miles in Texas, Truck B drove 3,100 miles in Texas, and Truck C drove 1,700 miles in Texas, your total Texas miles for the fleet are 9,000.

Also calculate the grand total of all miles driven across every jurisdiction combined. You will need this number in the next steps.

Step 4: Calculate Total Gallons Consumed

Add up every gallon of fuel purchased by your fleet during the quarter, regardless of where it was purchased. This includes diesel, gasoline, or any other IFTA-reportable fuel type. If you operate vehicles using different fuel types, keep them on separate schedules because tax rates differ between diesel and gasoline.

Your total gallons figure represents all fuel consumed by IFTA-qualified vehicles. Do not include fuel purchased for non-qualified vehicles such as passenger cars or light-duty trucks under 26,000 lbs that do not meet IFTA requirements.

Step 5: Determine Fleet MPG

Fleet miles per gallon (MPG) is the single number that drives your entire IFTA calculation. The formula is simple:

Fleet MPG = Total Miles Driven (all jurisdictions) / Total Gallons Consumed

For example, if your fleet drove 120,000 total miles and consumed 20,000 gallons of diesel, your fleet MPG is:

120,000 miles / 20,000 gallons = 6.0 MPG

This average is applied uniformly across every jurisdiction. IFTA does not allow you to use different MPG figures for different states; it is one fleet-wide average for the quarter. Round your MPG to the nearest hundredth (e.g., 6.03) for accuracy, since small differences in MPG multiply across thousands of miles.

Step 6: Calculate Taxable Gallons per State

For each jurisdiction, divide the miles driven in that state by your fleet MPG. The result is the number of gallons your fleet is deemed to have consumed in that state.

Taxable Gallons in State = State Miles / Fleet MPG

Using the earlier example with 6.0 MPG and 9,000 miles in Texas:

9,000 miles / 6.0 MPG = 1,500 taxable gallons in Texas

Repeat this calculation for every state and province where your fleet operated. The sum of taxable gallons across all jurisdictions should approximately equal your total gallons consumed (with minor rounding differences).

Step 7: Apply Tax Rates and Calculate Tax Due

Now compare the taxable gallons (what you consumed) in each state against the gallons actually purchased in that state. Then multiply the difference by the state's current fuel tax rate.

Net Taxable Gallons = Taxable Gallons in State - Gallons Purchased in State

Tax Due (or Credit) = Net Taxable Gallons x State Tax Rate

Continuing the Texas example: if you consumed 1,500 taxable gallons in Texas but purchased 2,000 gallons there, your net taxable gallons are -500. At Texas's diesel rate of approximately $0.20/gallon:

-500 gallons x $0.20 = -$100.00 (a credit of $100)

This means you overpaid Texas by $100 through fuel purchases and will receive a credit. Conversely, if you drove heavily through a state but purchased little fuel there, you will owe that state additional tax.

For the current tax rate for every state, see our IFTA tax rates by state 2026 reference guide.

Sum the tax due and credits across all jurisdictions. The net amount is what you owe (or what is credited to you) for the quarter.

Step 8: Complete and Submit the Return

Most base jurisdictions now offer electronic filing through their web portal. Log in to your base jurisdiction's IFTA filing system and enter the data for each jurisdiction: total miles, taxable gallons, gallons purchased, tax rate, and net tax. The system typically pre-fills current tax rates.

Review the return carefully before submitting. Double-check that total miles across all jurisdictions match your records. Verify that total fuel gallons match your fuel purchase documentation. Confirm the system is using the correct quarter's tax rates.

Submit the return and pay any amount due by the deadline. Payment methods vary by state but typically include ACH, credit card, or check. If you have a net credit, it will usually be applied to your next quarter's filing automatically.

Quarterly Filing Deadlines

IFTA returns are due on the last day of the month following the end of each quarter. Missing a deadline triggers automatic penalties and interest.

Set a reminder at least two weeks before each deadline to begin compiling your records. Waiting until the last day invites errors and puts your compliance at risk. If the deadline falls on a weekend or holiday, the due date is typically the next business day, but this varies by jurisdiction, so check with your base state.

Common IFTA Filing Mistakes

Auditors see the same errors repeatedly. Avoid these common mistakes to stay compliant and prevent costly adjustments:

• Inaccurate mileage by jurisdiction: This is the number one audit finding. Estimated mileage or routes that do not match actual GPS data will trigger adjustments and penalties. Always use the most accurate mileage source available.
• Missing or incomplete fuel receipts: If you cannot prove a fuel purchase with a valid receipt, the auditor will disallow the credit. Ensure every receipt shows the required details: date, seller, location, gallons, fuel type, and vehicle identification.
• Failing to file a zero return: If your trucks did not operate during a quarter, you must still file a return showing zero miles and zero gallons. Not filing is treated the same as filing late.
• Using incorrect tax rates: IFTA tax rates change quarterly in some jurisdictions. Always use the rates effective for the specific quarter you are filing, not the current rates. Check the current rate tables before filing.
• Mixing fuel types: Diesel and gasoline have different tax rates. If your fleet uses both fuel types, they must be reported on separate schedules. Combining them on a single schedule will produce incorrect results.
• Excluding non-revenue miles: Deadhead miles, bobtail miles, and personal conveyance miles in qualified vehicles must all be included in your mileage totals. Only miles in non-qualified vehicles are excluded.

How FleetLegend Automates IFTA Filing

Filing IFTA manually is tedious and error-prone. FleetLegend's IFTA reporting feature automates the most time-consuming parts of the process:

• Automatic mileage by jurisdiction: FleetLegend integrates with telematics providers like Motive and Samsara to pull GPS-verified mileage data. State-line crossings are detected automatically, so you never have to estimate or manually calculate jurisdiction miles.
• Fuel card import: Fuel purchase data from your fleet fuel cards is imported directly into FleetLegend, organized by jurisdiction, vehicle, and date. No more sorting through stacks of receipts.
• Automated calculations: FleetLegend computes fleet MPG, taxable gallons per state, and net tax owed or credited for each jurisdiction. The calculations use the correct tax rates for the filing quarter.
• Quarterly report generation: Generate an audit-ready IFTA report with a single click. The report includes all supporting detail that auditors require, organized exactly how your base jurisdiction expects to see it.

Instead of spending hours assembling spreadsheets each quarter, FleetLegend users typically complete their IFTA filing preparation in minutes. Learn more about FleetLegend's IFTA features.

Frequently Asked Questions

What happens if I file my IFTA return late?

Late filing incurs a penalty of $50 or 10% of your net tax liability, whichever is greater. Interest also accrues on any unpaid tax from the original due date. If you repeatedly file late, your base jurisdiction can revoke your IFTA license, which prevents your vehicles from legally operating across state lines until the license is reinstated.

Do I need to file if my trucks did not operate this quarter?

Yes. You must file a zero return for any quarter in which your qualified vehicles did not travel in any IFTA jurisdiction. Failing to file a zero return is treated the same as failing to file altogether, and penalties will apply.

Can I amend an IFTA return after I submit it?

Yes. Most base jurisdictions allow you to file an amended return if you discover an error after submission. Contact your base jurisdiction's IFTA office for the specific amendment process. It is better to self-correct an error through an amendment than to have an auditor find it later, which may result in additional penalties.

How long do I need to keep my IFTA records?

IFTA requires you to retain all supporting records, including mileage logs, fuel receipts, and trip reports, for a minimum of four years from the filing date. If you are under audit, retain records until the audit is fully resolved, even if that extends beyond four years.

Conclusion

Filing IFTA quarterly does not have to be a dreaded administrative burden. With proper systems in place - GPS-based mileage tracking, organized fuel records, and a clear step-by-step process - you can complete your filing accurately and on time every quarter. The carriers who struggle are those relying on estimates and last-minute data gathering. The carriers who breeze through are those with automated mileage tracking and fuel card imports. FleetLegend handles the tedious parts automatically, generating audit-ready IFTA reports in minutes instead of hours.