The IFTA fuel tax calculator above computes your quarterly fuel tax liability across all states you operated in. IFTA (International Fuel Tax Agreement) requires interstate carriers to file quarterly returns reconciling fuel taxes paid at the pump against fuel taxes owed based on miles driven per state. If you drove more miles in high-tax states than where you fueled, you owe the difference. If you fueled in high-tax states and drove in low-tax states, you receive a refund.
IFTA quarterly filing is mandatory for any qualifying commercial vehicle — but calculating the actual tax liability across 48 jurisdictions, each with different diesel rates that change every quarter, is where most operators make mistakes or waste time. This page gives you the calculation tool, the current rates, and the step-by-step method.
Jump straight to the calculator
Add your states, enter miles and fuel purchased, and get your Q2 2026 IFTA tax breakdown in under two minutes.
Use the IFTA Calculator ↓IFTA Fuel Tax Calculator
Enter your miles per state and fuel purchased to calculate quarterly IFTA tax owed or refund due. Rates reflect Q2 2026 IFTA diesel rate matrix. Verify current rates at IFTA Inc. →
What Is IFTA Fuel Tax?
The International Fuel Tax Agreement is a compact between 48 US states and 10 Canadian provinces that simplifies fuel tax collection for interstate commercial carriers. Before IFTA, operators had to buy separate fuel use permits for every state they entered. IFTA replaced that with a single quarterly filing with your base state.
Here is how it works in practice: you pay fuel taxes at the pump whenever you fill up. Those taxes go to the state where you fueled. But the fuel tax you owe is based on where you actually drove — not where you bought the fuel. IFTA reconciles the difference quarterly. Your base state collects any net payment and distributes funds to other states; it processes any refunds you are owed.
IFTA licenses are issued by your base state — the state where your vehicles are registered and where you maintain operational records. The license must be renewed annually. Each qualifying vehicle must carry a copy of the IFTA license (or the cab card) at all times.
Q1 (Jan–Mar): April 30 · Q2 (Apr–Jun): July 31 · Q3 (Jul–Sep): October 31 · Q4 (Oct–Dec): January 31. Late filing penalty: greater of $50 or 10% of net tax owed.
All trip records and fuel receipts must be kept for 4 years from the filing due date. Auditors can review mileage logs, odometer readings, GPS data, ELD exports, and fuel purchase receipts.
IFTA covers diesel, gasoline, propane, LNG, CNG, methanol, ethanol, and E85. Each fuel type is tracked and reported separately. Most Class 8 trucking involves diesel — this calculator is configured for diesel rates.
For IFTA filing requirements, license applications, and your base state's procedures, see the official IFTA Inc. resource → Also see our guide: IFTA Filing Requirements — Complete 2026 Guide
How the IFTA Fuel Tax Calculator Works
Our trucking fuel tax calculator uses the same methodology as your official IFTA quarterly return. Here is exactly what it calculates and why each input matters.
Enter your truck's average MPG for the quarter. The calculator divides your total miles by MPG to estimate total gallons consumed. It then distributes those gallons across states proportional to miles driven. This is the IFTA-standard method for carriers without per-state fuel consumption tracking.
Enter miles driven in each state for the quarter. Pull this from your trip logs, ELD reports, or RODS. Accuracy here is critical — IFTA auditors verify mileage against trip records and GPS data. Over-reporting miles in low-tax states is a common audit trigger.
Enter gallons purchased in each state from your fuel receipts. Every gallon you buy at the pump in a state generates a tax credit for that state's IFTA rate. The credit offsets your tax obligation in that state. Keeping organized fuel receipts by state is required for audit defense.
For each state: (taxable gallons × state rate) − fuel tax credit = net tax. States where you drove more relative to fuel purchased generate tax owed. States where you purchased more fuel than your proportional consumption generate a refund credit. All state results sum to your quarterly net position.
IFTA Fuel Tax Rates by State (Q2 2026)
IFTA diesel rates vary dramatically by state — from 18.4¢/gallon in Mississippi to over 100¢/gallon in California. This range means that a driver doing a California–Texas run faces very different tax exposure depending on where they fuel up. The table below shows selected state rates for reference. The ifta fuel tax calculator by state above uses the full 48-jurisdiction rate set.
Source: IFTA Inc. Q2 2026 rate matrix and state revenue department publications. Rates are subject to change each quarter. Verify at iftach.org before filing.
Key planning insight: California, Pennsylvania, and Illinois have the highest diesel tax rates. If you regularly run through these states, fueling up just before crossing into them can generate IFTA credits that offset taxes owed in lower-rate states you transit through. This is legal fuel tax planning — not evasion.
Also see: DOT Preventive Maintenance Requirements and HOS Calculator — two other compliance tools used by owner-operators in the same workflow.
How to Calculate IFTA Fuel Tax — Step-by-Step Method
Here is the manual calculation method that the IFTA mileage calculator above automates. Walk through this once to understand what the numbers mean.
Pull your trip logs or ELD reports for the quarter. Total the miles driven within each IFTA jurisdiction. Every state you crossed — even if you only drove 50 miles through it — must be reported. "Driven through" counts.
Divide total miles by your average MPG for the quarter. Use actual fleet data, not manufacturer specs. If your MPG varies significantly by load or terrain, calculate separately for loaded vs. deadhead miles for higher accuracy.
For each state: (state miles ÷ total miles) × total gallons consumed = taxable gallons in that state. This tells you how many gallons you are deemed to have 'used' in each jurisdiction.
Multiply taxable gallons by each state's IFTA diesel rate. Convert rate from cents to dollars (divide by 100).
For each state, multiply gallons purchased there by the state's IFTA rate. This is the tax you already paid at the pump in that state.
Net tax = gross tax owed − fuel credit. If positive, you owe that amount to the jurisdiction. If negative, you have a credit (refund from that state). Sum all states for your quarterly net position.
Owner-Operator IFTA Calculation Example (Q2 2026)
This is a worked example for a single owner-operator running a Texas-to-Illinois corridor during Q2 2026. Use the owner operator ifta calculator above to run your own numbers.
| State | Miles | Gal Purchased | State Rate |
|---|---|---|---|
| Texas | 1,800 | 220 | 20.0¢ |
| Oklahoma | 350 | 45 | 19.0¢ |
| Kansas | 420 | 60 | 26.0¢ |
| Missouri | 380 | 50 | 19.5¢ |
| Illinois | 300 | 0 | 59.56¢ |
| TOTAL | 3,250 | 375 | — |
| State | Taxable Gal | Gross Tax | Credit | Net |
|---|---|---|---|---|
| Texas | 276.9 | $55.38 | $44.00 | $11.38 |
| Oklahoma | 53.8 | $10.23 | $8.55 | $1.68 |
| Kansas | 64.6 | $16.80 | $15.60 | $1.20 |
| Missouri | 58.5 | $11.40 | $9.75 | $1.65 |
| Illinois | 46.2 | $27.54 | $0.00 | $27.54 |
This example illustrates the Illinois problem common to Midwest corridor operators: at 59.56¢/gallon, Illinois is one of the highest-rate IFTA states. Running 300 miles through Illinois without fueling there means you owe the full proportional tax with zero credit to offset it. Fueling in Indiana (53¢/gal) or Missouri (19.5¢/gal) before crossing into Illinois is standard practice among experienced operators.
For fleet-level compliance tracking: TruckComplianceHQ Dashboard tracks CDL expirations, DOT medicals, and annual inspection due dates — the records you need alongside IFTA for a complete compliance posture. Also see: Annual DOT Inspection Due Date Calculator
Don't just calculate IFTA — track everything automatically
TruckComplianceHQ tracks CDL expirations, drug testing schedules, DOT medicals, and annual inspection due dates. The compliance data that goes alongside your IFTA filing every quarter. Free for the first 5 drivers.
Run Free Compliance Check →Full dashboard trial →Frequently Asked Questions — IFTA Fuel Tax
IFTA diesel rates sourced from the IFTA Inc. quarterly rate matrix and individual state revenue department publications. Rates are updated quarterly — always verify the current quarter's rates before filing your IFTA return. This calculator is for planning and estimation purposes. It is not a substitute for your official state IFTA return form. Consult your base state's motor carrier division or a qualified trucking accountant for filing questions.
Regulatory References & Data Sources
Use the Free IFTA Fuel Tax Calculator Every Quarter
Bookmark this page. Come back every quarter — Q1 due April 30, Q2 due July 31, Q3 due October 31, Q4 due January 31. The IFTA fuel tax calculator is updated with new rates each quarter so your estimates stay accurate.