Instant IFTA Fuel Tax Calculator
Quickly calculate quarterly International Fuel Tax Agreement (IFTA) dues and credits across all 48 US states. Enter miles driven and gallons purchased by state.
| Jurisdiction | Miles Driven | Gallons Purchased | Taxable Gallons | Tax Rate ($/gal) | Net Tax Due / (Credit) | Action |
|---|
How Quarterly IFTA Fuel Tax Works for US Motor Carriers
I write straightforward guides to help motor carriers, dispatchers, and brokers navigate federal transportation safety regulations.
The International Fuel Tax Agreement (IFTA) is an agreement between the 48 contiguous US states and 10 Canadian provinces to simplify the reporting of fuel taxes by commercial interstate motor carriers.
Instead of purchasing temporary fuel trip permits each time you cross a state line or filing separate tax returns in 15 different state revenue departments, carriers register with their home base jurisdiction and file one consolidated quarterly return.
The base state takes care of distributing payments or collecting credits across all the member states where your trucks traveled.
The "Pump Price" Trap: Why Cheap Fuel Can Cost You More
Many rookie truckers and owner-operators look only at the posted sign at the truck stop when fueling up. But under IFTA rules, that posted price already includes state diesel taxes, which differ drastically across state borders:
Example A: Pumping Cheap Fuel in Oklahoma
You fuel up in Oklahoma where the state diesel tax is only $0.190 per gallon. The pump price looks very cheap on the highway sign.
Then you drive all those miles through Pennsylvania (tax rate: $0.623 per gallon) without buying diesel there. At the end of the quarter, you owe Pennsylvania $0.433 per gallon in back taxes for every gallon burned in their state!
Example B: Earning Fuel Tax Credits
If you purchase diesel in a high-tax state like Indiana ($0.350/gal) or Pennsylvania ($0.623/gal), you prepay those tax dollars at the pump.
When you later drive through lower-tax states, those prepaid tax dollars turn into substantial IFTA credits, wiping out your tax dues or generating a quarterly cash refund from your home state.
Pro Tip for Dispatchers: Always compare the net fuel price before tax (Pump Price minus State Fuel Tax) when planning multi-state fuel stops along your freight lane.
2026 IFTA Quarterly Due Dates & Filing Schedule
IFTA returns must be postmarked or filed electronically by midnight on the due date. If the due date falls on a weekend or federal holiday, it extends to the next business day.
| Quarter | Travel Period | Filing Deadline | Late Penalty |
|---|---|---|---|
| Quarter 1 (Q1) | January 1 – March 31 | April 30, 2026 | $50 or 10% of tax due |
| Quarter 2 (Q2) | April 1 – June 30 | July 31, 2026 | $50 or 10% of tax due |
| Quarter 3 (Q3) | July 1 – September 30 | October 31, 2026 | $50 or 10% of tax due |
| Quarter 4 (Q4) | October 1 – December 31 | January 31, 2027 | $50 or 10% of tax due |
3 Steps to Avoid Costly IFTA Audit Penalties
State auditors routinely audit motor carrier fuel records. Follow these three rules every quarter to pass audits cleanly:
Keep Itemized Receipts
Auditors automatically reject credit card billing summaries. You must retain original fuel receipts showing date, seller name, gallons, price, fuel type, and vehicle unit number.
Reconcile ELD Mileage
Compare your Electronic Logging Device (ELD) GPS state mileage against beginning and ending hub odometer readings every quarter to eliminate gap miles.
Retain Files for 4 Years
Federal IFTA statutes require motor carriers to retain all quarterly fuel invoices, logbooks, and trip reports for at least 4 years from the date of the return.
Frequently Asked Questions About IFTA Reporting
Essential answers for owner-operators and fleet managers filing quarterly fuel taxes.
Total miles driven are divided by total fuel purchased to find average fleet MPG. State miles are then divided by this MPG to calculate taxable gallons in each jurisdiction. Net tax due or credit is determined by subtracting purchased gallons from taxable gallons and multiplying by the state tax rate.
You receive a fuel tax credit for that state. That credit directly offsets taxes owed to states where you burned more fuel than purchased, or can be refunded by your base jurisdiction.
IFTA returns are due on the last day of the month following each calendar quarter: Q1 is due April 30; Q2 is due July 31; Q3 is due October 31; and Q4 is due January 31.
Pump prices include state fuel taxes, which vary widely (e.g., $0.623/gal in Pennsylvania vs $0.190/gal in Oklahoma). If you buy cheap fuel in a low-tax state and drive through a high-tax state, you will owe the difference at the end of the quarter.
Any commercial motor vehicle used for interstate transport that has two axles and a Gross Vehicle Weight (GVW) over 26,000 lbs, has three or more axles regardless of weight, or is used in combination when the gross weight exceeds 26,000 lbs.
Filing late triggers an automatic $50 minimum fine or 10% of the total tax due (whichever is greater), plus monthly interest charges of approximately 1% until paid. Repeated late filings can result in IFTA license revocation.
Carriers must maintain itemized fuel receipts (showing vendor, location, date, gallons, fuel type, and truck unit number), monthly vehicle mileage reports, and ELD GPS data for at least 4 years from the date of filing.
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