Free tool
IFTA fuel tax calculator
Enter the miles you ran and the gallons you bought in each state. The calculator works out fleet MPG, taxable gallons, net gallons and tax due using this quarter's official rates. No signup needed.
Quarterly fuel tax worksheet
Enter miles driven and gallons bought in each state. Diesel, official 3rd Quarter 2026 rates.
Add miles and gallons for at least one state to see your numbers.
Estimate only. Rates are the official IFTA, Inc. Special Diesel rates for 3rd Quarter 2026 in U.S. dollars per gallon, including the Kentucky and Virginia surcharges on taxable gallons. You remain the filer of record with your base jurisdiction — always check the numbers against your own records before filing.
How the math works
The five steps, with a spreadsheet version you can copy.
Taxable miles explained
Deadhead, personal use, toll roads and off-highway miles.
Save every quarter
Keep worksheets on file and get deadline reminders. Flat pricing.
General information, not tax advice. You remain the filer of record; confirm requirements with your base jurisdiction.