Question 1

How does the IFTA calculator work?

Accepted Answer

Enter the miles you drove in each state or province this quarter plus the gallons of diesel you purchased in each. We compute your fleet MPG (total miles ÷ total gallons purchased), split total gallons consumed across jurisdictions based on miles, then multiply taxable gallons (consumed − purchased) by each jurisdiction's tax rate. Positive rows mean you owe; negative rows mean you're owed a credit. The net figure is what your base jurisdiction will collect or refund.

Question 2

Where do the rates come from?

Accepted Answer

We publish the rates from the IFTA Inc tax matrix (iftach.org), the canonical consolidated source every jurisdiction reports to. Our table is the latest quarterly matrix. If you’re filing for an older quarter, pull the rates for that period from iftach.org - our math works identically, just swap the rate values.

Question 3

What if I didn’t buy fuel in a state I drove through?

Accepted Answer

That’s the entire point of IFTA - you still owe fuel tax in any state your trucks burn fuel, regardless of where you bought it. A pass-through with zero gallons purchased will show up as 100% taxable gallons owed to that state. You offset by reporting the gallons you bought in states where you drove fewer miles than gallons pumped would cover.

Question 4

Does this handle Canadian provinces?

Accepted Answer

Yes. IFTA is a combined US + Canada agreement. The 10 Canadian provinces publish their rates in USD-per-gallon inside the same IFTA matrix, so our calculator works identically regardless of whether your miles were logged in Texas or Ontario.

Question 5

What about Oregon?

Accepted Answer

Oregon has no diesel tax - they fund highways through a weight-mile tax paid by every commercial vehicle 26,000 lbs or heavier. Oregon rows on your IFTA return always compute to $0, but you still have to file the zero row to stay in compliance. Our permit calculator covers the Oregon weight-mile tax separately.

Question 6

Will this file my IFTA return?

Accepted Answer

No. This tool only computes the numbers. You still file with your base jurisdiction (the state your IFTA license is issued from). Most base jurisdictions publish a web form that accepts the same numbers this calculator produces.

Free IFTA tax calculator

Common questions, plainly answered.

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