IFTA mileage calculator
Free IFTA calculator for quarterly fuel tax across all 48 contiguous states. Enter miles driven and gallons purchased per jurisdiction to see net tax owed — or credits — before the Apr 30 / Jul 31 / Oct 31 / Jan 31 deadlines.
Understanding IFTA and Your Filing Obligations
The International Fuel Tax Agreement (IFTA) applies to any carrier operating a qualified motor vehicle — over 26,000 lbs or with 3+ axles — across state lines. If that describes your operation, you file quarterly returns reporting miles driven and fuel purchased in each jurisdiction. The math is straightforward but tedious: each state calculates taxable gallons based on your fleet MPG, then applies its own tax rate. States where you bought more fuel than you consumed give you a credit; states where you drove more than you fueled owe a balance. Getting it wrong means penalties and interest, and the filing deadlines (April 30, July 31, October 31, January 31) come up fast. Under the IFTA Articles of Agreement (IFTA, Inc., Articles of Agreement manual dated August 26, 2026), IFTA mileage is reported as two distance figures. Total Distance, section R266, means all miles or kilometers traveled during the tax reporting period by every qualified vehicle in the licensee fleet, regardless of whether the miles or kilometers are considered taxable or nontaxable by a jurisdiction. In-Jurisdiction Distance, section R224, means the total number of miles or kilometers operated by qualified motor vehicles within a jurisdiction, including miles or kilometers operated under an IFTA temporary permit, and it does not include miles or kilometers operated on a fuel tax trip permit or exempted from fuel taxation by a jurisdiction.
This calculator does the heavy lifting. Enter your miles driven and gallons purchased per state, and it computes your net tax or credit for each jurisdiction instantly. It accounts for current state tax rates and surcharges so you can estimate your quarterly liability before you sit down with your accountant. For a deeper walkthrough of the filing process, read our IFTA filing guide.
Keep in mind: this tool provides estimates for planning. Your official filing should use actual mileage records and fuel receipts through your base jurisdiction's IFTA portal. But having a reliable estimate before filing season means no surprises — and better cash flow planning all quarter long.
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Frequently Asked Questions
What is IFTA and who needs to file?
IFTA (International Fuel Tax Agreement) is a fuel tax collection agreement between 48 US states and 10 Canadian provinces. If you operate a qualified motor vehicle (over 26,000 lbs or 3+ axles) across state lines, you must file quarterly IFTA returns reporting miles driven and fuel purchased in each jurisdiction.
When are IFTA returns due?
IFTA returns are filed quarterly. Q1 (Jan-Mar) is due April 30, Q2 (Apr-Jun) is due July 31, Q3 (Jul-Sep) is due October 31, and Q4 (Oct-Dec) is due January 31. Late filings incur penalties and interest.
How does the IFTA calculation work?
IFTA calculates fuel tax owed per state based on miles driven in that state divided by your fleet MPG. This gives you 'taxable gallons' — the fuel you theoretically consumed in that state. If you purchased more fuel than you consumed in a state, you get a credit. If you consumed more than you purchased, you owe tax at that state's rate.
Which states have the highest fuel tax rates?
As of current rates, California, Pennsylvania, Indiana, and Washington have some of the highest diesel fuel tax rates, while Alaska, Oklahoma, and Mississippi have among the lowest. Tax rates change periodically, so always verify with your state's IFTA office before filing.
Does this calculator replace my official IFTA filing?
No. This calculator provides estimates for planning purposes. For your official quarterly filing, use your actual mileage records and fuel receipts, and file through your base jurisdiction's IFTA portal or through your accountant.
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