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STATELINE

IFTA basics · 4 minute read

IFTA in plain words.

What it is, whether you need it, when it's due and how the math works, with one real trip worked all the way through.

The short version
  • IFTA is one fuel tax return for every state and province you drive in, filed with your home state four times a year.
  • You owe each state for the fuel you burned there, and get credit for the tax you paid at the pump.
  • All you need is miles by state and your fuel receipts. The rest is arithmetic.

01Do you need IFTA?

Yes, if your truck crosses into more than one state or province and it's one of these:

2 axles
and over 26,000 lb gross weight
3+ axles
at any weight
Combination
over 26,000 lb combined

Stay in one state, or only drive under a trip permit? You don't file IFTA for those miles.

02When it's due

Four returns a year, each due the last day of the month after the quarter ends. File even if you drove zero miles.

  1. Q1
    Jan to Mar
    Due
    April 30
  2. Q2
    Apr to Jun
    Due
    July 31
  3. Q3Next
    Jul to Sep
    Due
    October 31
  4. Q4
    Oct to Dec
    Due
    January 31

03How the math works

Four steps, using one example trip: Dallas, TX to Denver, CO, 1,000 miles, 150 gallons bought in Texas.

  1. 1
    Find your fleet MPG

    All the miles you drove this quarter divided by all the gallons you bought. Round to two decimals.

    1,000 mi ÷ 150 gal
    = 6.67 MPG
  2. 2
    Turn each state's miles into gallons

    That's the fuel you burned in that state, rounded to the nearest gallon.

    420 mi in Texas ÷ 6.67
    = 63 gal
  3. 3
    Take off what you bought there

    Burned minus bought, times the state's rate. A minus is a credit: you paid that tax at the pump already.

    (63 − 150) × $0.200
    = −$17.40
  4. 4
    Add up every state

    Positive means you owe your base state. Negative means a refund or a credit on the next quarter.

    $15.08 + $8.82 + −$17.40
    = $6.50
Run your own numbers

04Records to keep

Keep everything for four years. An audit asks for the trip sheets and receipts, not a summary.

Every trip
  • Date and route
  • Odometer at the start, at each state line and at the end
  • Truck or unit number
  • Total miles
Every fuel stop
  • Date and seller
  • City and state
  • Gallons and price per gallon
  • Truck or unit number

The trip pack's printable sheets cover all of this. See the pack.

05Words you'll see on the form

Base jurisdiction
The state or province where your truck is registered for IFTA. You file one return there and it splits the money with everyone else.
Fleet MPG
All your miles for the quarter divided by all your gallons, rounded to two decimals. Every state uses this one number.
Taxable miles
Miles that count for fuel tax. For most trucks, every mile in the state.
Taxable gallons
Taxable miles in a state divided by your fleet MPG. The fuel you burned there.
Tax-paid gallons
Fuel you bought at the pump, where tax was already in the price. These earn you a credit in that state.
Surcharge
An extra charge per gallon in Kentucky and Virginia. It's charged on gallons burned and never credited back.

This is a plain-words guide, not tax advice. Your base state's instructions are the final word.