How do I estimate my IFTA quarterly fuel tax by jurisdiction?
Divide the miles you ran in each jurisdiction by your fleet average MPG to get the taxable gallons that jurisdiction is owed, subtract the tax-paid gallons you bought there, and multiply the net gallons by that jurisdiction's current per-gallon rate. Add the results across all jurisdictions, with credits offsetting amounts due, to get the net quarterly liability you remit through your base jurisdiction.
Founded in 2008 by Scott Elliott in Minnesota, Strong Tower Consulting, LLC (Minnesota File No. 2948628-2) has advised carriers for more than 18 years on the TMS, ELD, and fuel card data that feed a defensible IFTA return.
The three starting rows are example values. The example rates (0.30, 0.28, 0.32) are placeholders. Replace every rate with the current quarter figure for that jurisdiction and fuel type from the IFTA tax rate matrix at iftach.org. This page does not store any real state or provincial rate.
Total miles in all jurisdictions divided by total gallons placed in the fuel tanks of qualified vehicles. Use the same MPG for every jurisdiction.
One row per state or province. Miles are total miles driven in that jurisdiction, loaded or empty. Tax-paid gallons are the gallons you bought at the pump in that jurisdiction with tax included. Rate is dollars per gallon from the current IFTA matrix.
Results from your inputs
| Jurisdiction | Miles | Taxable gallons | Tax-paid gallons | Net gallons | Rate | Tax due or (credit) |
|---|---|---|---|---|---|---|
| Totals | 0 | 0 | 0 | 0 | $0.00 |
Show the math
How the estimator works
IFTA is an apportionment agreement. You file one return with your base jurisdiction, and the fuel tax is distributed to every member jurisdiction in proportion to the miles you drove there. The estimator follows the same five steps a return does.
- Total the miles. Add the miles from every jurisdiction row. This is the quarter total for all qualified vehicles.
- Convert total miles to total taxable gallons. Total miles divided by fleet average MPG. This is the fuel the fleet consumed, regardless of where it was bought.
- Apportion taxable gallons to each jurisdiction. Miles in that jurisdiction divided by the same fleet MPG.
- Net out the tax already paid at the pump. Taxable gallons minus tax-paid gallons purchased in that jurisdiction. A negative result is a credit.
- Price the net gallons. Net gallons times the per-gallon rate you entered for that jurisdiction. Sum every row to get the net quarterly liability.
total_miles = sum(jurisdiction_miles)
total_taxable_gallons = total_miles / fleet_mpg
taxable_gallons[j] = jurisdiction_miles[j] / fleet_mpg
net_gallons[j] = taxable_gallons[j] - tax_paid_gallons[j]
tax_due_or_credit[j] = net_gallons[j] x rate[j]
net_quarterly = sum(tax_due_or_credit[j])
Open "Show the math" above to see these lines filled in with your current rows.
What is out of scope
Surcharge jurisdictions are out of scope. A few members charge a surcharge on top of the base fuel tax, and that surcharge is reported on a separate line against taxable gallons, not net gallons, with no credit for tax paid at the pump. Interest on late or amended returns and penalties are also out of scope. The estimator uses one fuel type and treats every mile as taxable. If you run exempt miles, toll road exemptions, or more than one fuel type, your fuel tax software or preparer handles those lines.
Where the inputs should come from
Miles by jurisdiction
Your ELD or telematics platform produces state line crossings and distance by jurisdiction. The totals on the return should reconcile to your odometer readings and to the dispatch miles in your TMS. When those three sources disagree, auditors ask why. Strong Tower's ELD and EDI integration practice is built around making ELD distance data flow into the TMS so that jurisdiction miles are not retyped from a printout.
Tax-paid gallons
Fuel card transaction files carry the purchase jurisdiction and gallons. Retail receipts for cash purchases must be kept and keyed. The gallon figure that counts is fuel placed in the propulsion tank of a qualified vehicle with the jurisdiction tax included in the price. Reefer fuel and bulk fuel pumped without tax do not belong in this column.
Fleet MPG
Total miles divided by total gallons for the quarter, across all qualified vehicles. The same MPG applies to every jurisdiction. If you keep MPG by truck in a SQL reporting layer, the quarter average should tie to the sum of those figures, and an MPG that swings sharply from one quarter to the next is the first thing an auditor will question.
How a carrier uses the result
A positive net liability means the fleet drove more in jurisdictions where it bought less fuel than its mileage share. A negative figure, labeled as a credit above, means the fleet bought more tax-paid fuel than it consumed in those jurisdictions and the difference comes back through the base jurisdiction. Fuel buying strategy can move money between the pump price and the quarterly return, but the total tax owed is set by miles and MPG, not by where you fill. Carriers that want to model that tradeoff over a network of lanes usually bring it into the dispatch optimization work alongside routing and fuel stop selection. Fleets that are moving to a new TMS can set up the mileage and fuel feeds as part of the TMS implementation so the first quarter on the new system reconciles cleanly.
Frequently asked questions
How does IFTA decide which jurisdiction is owed fuel tax?
IFTA apportions fuel tax by where the miles were driven, not by where the fuel was bought. Each jurisdiction is credited with taxable gallons equal to the miles you ran there divided by your fleet average MPG for the quarter. The tax you already paid at the pump in that jurisdiction is then subtracted, so a jurisdiction where you drove a lot but bought little fuel shows tax due, and the reverse shows a credit.
Where do the per-gallon tax rates in this estimator come from?
You enter them. Rates change by quarter and by fuel type, so this page does not store any real state or provincial rate. Take each rate from the current quarter tax rate matrix published by the International Fuel Tax Association at iftach.org and type it into the row for that jurisdiction. The example rows use clearly labeled example rates that are placeholders only.
Why can a jurisdiction show a credit instead of tax due?
A credit appears when the tax-paid gallons you purchased in a jurisdiction exceed the taxable gallons apportioned to it from your miles. You paid that jurisdiction more tax at the pump than your mileage share required. On the return, credits in one jurisdiction offset tax due in others, and the net quarterly figure is what you remit or receive through your base jurisdiction.
What does this IFTA estimator leave out?
It leaves out surcharge jurisdictions, which add a second line with a separate rate, and it leaves out interest and penalties on late or amended returns. It also does not split fuel types or handle tax-exempt miles. It is a planning estimate that shows the core apportionment math. Your filed return should come from your fuel tax software or your preparer using the official rate matrix.
This estimator is a planning estimate, not tax, legal, or accounting advice. Rates, surcharges, exemptions, and filing rules change. Confirm every figure against the current IFTA tax rate matrix and your base jurisdiction's instructions before filing.
Make the IFTA return reconcile to the TMS the first time.
Strong Tower Consulting provides independent systems architecture, feasibility audits, and engineering roadmaps for motor carriers and freight brokers. Contact our advisory team or call 763-244-1373 to talk through how ELD miles, fuel card files, and TMS dispatch data should fit together for fuel tax reporting.
Strong Tower Consulting, LLC and Exspeedite LLC are separately organized sister companies under common ownership.