How do I prepare and file my IFTA quarterly return?

Chapter 01

What is the IFTA return, and when is it due?

The IFTA return reports the miles your trucks drove and the fuel they took on in each State over three months. States tax the fuel burned on their roads, each at its own rate. Under IFTA, you report to one State, your base State, and it settles with all the others (the IFTA Articles of Agreement). The quarters end on March 31, June 30, September 30 and December 31. Each return is due on the last day of the next month.

Here is how that looks in real life. Say you run two trucks out of West Virginia. Both are tractors pulling loaded trailers, and both run through Ohio, Pennsylvania, Kentucky and Indiana. IFTA covers trucks like yours. It covers any truck with three or more axles. It also covers a truck with two axles, or a truck and trailer together, over 26,000 pounds. You need an IFTA license once such a truck runs in two or more member States (the rulebook’s licensing rule). West Virginia issued your license and decals. Your trucks are registered there, your records are kept there, and your trucks drive there. That makes it your base State. Getting and keeping the license is its own job, and our guide to the IFTA license and decals covers it.

The third quarter of 2026 ran from July 1 to September 30. Its return would normally be due October 31, 2026. But this year that day is a Saturday. The rule moves a due date that falls on a weekend or a legal holiday to the next business day. So the real due date is Monday, November 2 (the rule on due dates). Aim for October 31 anyway. Then no argument about counting days can hurt you.

Owners search for IFTA due dates every quarter, but the standard dates stay the same. The first quarter is due April 30, the second July 31, the third October 31 and the fourth January 31. The rule says that “the tax return and full payment of taxes shall be due” on that last day. Look at the words “full payment”. A return filed on time without the money still counts as late (the rule on late filing).

One exception decides whether this is your job at all. If your trucks run leased onto another carrier for 30 days or more, the lease says who files. If the lease says nothing, the carrier files, not you (the rule on leased trucks). Your trucks run under your own authority, so the West Virginia return is yours.

Why file a return at all, when you paid tax at the pump? Because the tax in the pump price goes to the State where you bought the fuel. But each State is owed tax on the fuel burned on its roads. Your IFTA tax return reconciles the two. Fuel bought in one State and burned in another earns a credit in the first State and a bill in the second. The rulebook promises “full credit or refund for tax-paid fuel used outside the jurisdiction where the fuel was purchased” (the rule on credits). In plain words, the tax on each gallon ends up with the State where you burned it.

Chapter 02

How do I match up my miles and fuel?

You need two numbers for each truck, split by State: the miles it drove and the gallons put in its tank. Take the miles from your electronic logging device (ELD) or GPS, and check them against trip sheets and odometer readings. Take the fuel from your fuel card report and receipts. Every gallon goes into the total, even one with no receipt, because the total sets your miles per gallon (IFTA’s rulebook). Only fuel with a receipt can earn a credit for tax paid at the pump.

Back to your two trucks. It is Monday, October 5, 2026, and you sit down with the third quarter. You pull the ELD report for each truck from July 1 to September 30. If your ELD or GPS can show miles by State, use that report. Truck 1 shows 32,000 miles. Truck 2 shows 27,600.

Now check those miles another way. Look at each truck’s odometer reading on July 1 and on September 30. The difference should match the ELD total. Truck 1’s does. Truck 2’s odometer shows 400 more miles than its ELD. You find a gap of two days in August, when the device was unplugged. Your driver’s trip sheets show two runs from Morgantown to Pittsburgh and back on those days. So you add those miles to Pennsylvania and West Virginia. Truck 2 now has 28,000 miles, and the fleet has 60,000. Every mile must be allocated to a State.

Next comes the fuel. Your fuel card report lists every fill by truck, date, State and gallons. Add any cash receipts your drivers kept. Truck 1 took 5,200 gallons, and truck 2 took 4,800. That makes 10,000 gallons for the fleet. Keep each receipt under the State where the pump stood, not where the truck is based.

Then run a quick check that catches many mistakes. Divide each truck’s miles by its gallons. Truck 1 comes to 6.15 miles per gallon, and truck 2 to 5.83. Both look like what those trucks usually get. If one truck suddenly showed unusually high mileage per gallon, check for a missing fuel receipt. If it showed unusually low mileage, check for missing miles or fuel put into something other than the truck.

What if a driver loses a receipt? The fuel still counts. IFTA’s board ruled that all fuel must be reported, “whether receipted or not, and whether taxed or not” (the rulebook, with the board’s rulings). So those gallons go into your total. You just cannot claim a credit for the tax on them. For that credit, you need a receipt, an invoice or a fuel card listing that shows the purchase and the tax. A receipt that was altered, or shows erasures, is not accepted unless you can show it is real.

You do not send receipts with the return (the rule on receipts). You keep them, with the ELD reports and trip sheets, in case your State asks. What a receipt must show is set out in the records IFTA expects you to keep. So is how long to keep everything, and what form your GPS data must be in. The same records are what carry you through an audit.

Chapter 03

How do I work out what I owe each State?

Divide your fleet’s total miles by its total gallons. That is your average miles per gallon, which the form calls fleet MPG. Divide the miles in each State by that number. The result is the fuel you burned there, which the form calls taxable gallons. Subtract the gallons you bought there with the tax paid. Then multiply what is left by that State’s rate for the quarter (the West Virginia return instructions).

Your fleet drove 60,000 miles on 10,000 gallons. So your fleet MPG is 6.00. IFTA’s rules have you carry it to two decimal places (IFTA’s Procedures Manual). You use one MPG for the whole fleet, not one per truck. Now divide each State’s miles by 6. West Virginia had 15,000 of your miles, so you burned 2,500 gallons there. Ohio had 18,000 miles and 3,000 gallons. Pennsylvania had 12,000 and 2,000. Kentucky had 9,000 and 1,500. Indiana had 6,000 and 1,000. Together that is 10,000 gallons again, as it should be.

The form asks for total miles and taxable miles in each State. For most trucks they are the same number. A few States do not tax some miles, and each State decides which. If you take miles off as nontaxable, you must keep proof (the West Virginia return instructions). Your trucks ran ordinary highway miles, so every mile is taxable.

Next, sort your receipts by State. These are your tax paid gallons: fuel you bought with that State’s tax in the price. You bought 4,000 gallons in West Virginia, 3,500 in Ohio, 2,500 in Kentucky, and none in Pennsylvania or Indiana. That also makes 10,000, because every gallon you bought has a receipt.

Each State sets its own rate. IFTA publishes all of them in one table each quarter, called the tax rate matrix (IFTA’s tax rate matrix). Use the table for the quarter you are filing, not the one for today. The rulebook says the return your State gives you shows the current rates (the rule on return forms). The rates below are round numbers we made up to show the math. Look up the real ones before you file. Here is your third quarter, State by State:

Read it one line at a time. In West Virginia you bought 1,500 gallons more than you burned there. You already paid West Virginia tax on those gallons, so you get it back as a credit of $600. In Pennsylvania you burned 2,000 gallons and bought none there, so you owe Pennsylvania $1,500. The credits and the bills are netted on the same return (the rule on credits). Your credits of $1,100 cover part of your bills of $2,250. You pay the rest: $1,150.

Notice what this means for where you buy fuel. Filling up in a State with a low tax does not escape the tax. You still owe each State for the fuel burned on its roads. The return only sorts out which State gets the tax.

Now the Kentucky surcharge line. A few States add a second tax on top of the fuel tax, and the rate table shows it on its own line, marked surcharge. In the table for the third quarter of 2026, Kentucky and Virginia each have one for diesel. Indiana has one too, but only for propane (IFTA’s rate table for the third quarter of 2026). The surcharge is charged on all the fuel you burned in that State, and fuel you bought there does not reduce it. West Virginia’s instructions say the surcharge “is always a tax due amount, never a tax credit” (the West Virginia return instructions). So your 1,500 Kentucky gallons, at the $0.10 we made up, cost $150. That holds even though you bought more fuel in Kentucky than you burned there.

Kentucky also brings a separate job. Five States charge heavy trucks their own tax based on weight and distance: Kentucky, New Mexico, New York, Oregon and Connecticut. Those taxes are not part of IFTA. They have their own accounts and returns, and this page does not cover them. The IFTA rate table shows the split too. In the table for the third quarter of 2026, Oregon’s line is empty (IFTA’s rate table for the third quarter of 2026).

Chapter 04

How do I file and pay it, and what if I am late?

You file with your base State, in the way it allows. The rulebook lets each base State take returns on its own form, on paper or online. The State also decides how you can pay (the IFTA Articles of Agreement). The return and the full payment must both arrive by the due date. If either one is late, your State can charge a penalty of $50 or 10% of the tax, whichever is more. It adds interest each month on the tax owed to each State.

On Monday, October 26, 2026, you fill in West Virginia’s return. Each State’s form looks a little different. But every one asks for the same things, because IFTA sets a standard form (IFTA’s Procedures Manual). It asks for total miles, total gallons and the fleet MPG. Then, for each State, it asks for total and taxable miles, taxable gallons, tax paid gallons and net taxable gallons. Last come the rate, the tax and any interest. Your State must give you the form, free, at least 30 days before the due date. Not getting it is no excuse for not filing (the rule on return forms).

Then you pay the $1,150. The whole amount goes to West Virginia, which passes each State its share. That one payment settles your fuel tax with every member State for the quarter (the rule on filing with the base State). How you pay is up to your base State. The rulebook allows payment “by any method of electronic transfer approved by the base jurisdiction”. Check which methods your State accepts well before the last day. And sign the return: West Virginia’s instructions say it is not complete without a signature (the West Virginia return instructions).

If your State takes paper returns and you mail yours, the postmark date counts as the filing date. The envelope must carry the right address and enough postage. A return handed in at the office counts on the day the staff sign for it (the rule on delivery). A return or payment sent online counts on the date your State’s own law sets.

Now suppose you had put it off, and filed and paid on Tuesday, November 10, eight days late. The rule says your State “may assess the licensee a penalty of $50.00 or 10 percent of delinquent taxes, whichever is greater”. That covers a return not filed, a return filed late, and tax underpaid (the rule on penalties). Ten percent of your $1,150 is $115. That is more than $50, so your State could charge you $115.

Interest comes on top. For a fleet based in the United States, the yearly rate is the federal rate on unpaid taxes plus 2 points. It is reset every January 1 and charged by the month (the rule on interest). For 2026, IFTA lists the rate as 9% a year (IFTA’s interest rate page). That makes 0.75% a month. It is counted State by State, on the tax owed to each one, and any part of a month counts as a full month. Your credits in West Virginia, Ohio and Kentucky do not shrink it. Pennsylvania’s $1,500 alone would draw $11.25 for those eight days.

A late return can cost more than money. If you do not file at all, your State can estimate your tax from whatever it has. It can also suspend or revoke your license (the rule on assessments). After late returns, it can make you post a bond. And it renews your license and decals for next year only when every return is filed and every tax paid. So a missed third quarter can leave your trucks without 2027 decals. The IFTA license guide explains renewal.

Some quarters end the other way, with a credit. Say you had bought most of your fuel in Pennsylvania. Then the return would show money owed to you. You can leave the credit on your account to cover later returns for up to eight quarters. Or you can ask for a refund, in writing unless your State refunds on its own. Once you ask, your State must pay a refund that is due within 90 days, or add interest. It can hold the refund if you owe fuel tax to any member State (the rules on credits and refunds).

Chapter 05

What if a truck sat parked all quarter?

You still file, and the return still covers the whole fleet. The parked truck simply adds no miles and no fuel. If no truck ran at all, you still file, and you mark the return to show you did not operate. The rule says returns “are required even if no operations were conducted or no taxable fuel was used” (the rule on reporting periods). In plain words, no miles still means a return.

Here is how that plays out. In October 2026, truck 2 goes into the shop for an engine rebuild, and it sits there until the new year. Truck 1 keeps running all fourth quarter, from October 1 to December 31. That return is due January 31, 2027. That day is a Sunday, so the due date moves to Monday, February 1 (the rule on due dates).

You fill in the return just as before. Truck 1’s miles and fuel go in. Truck 2 adds nothing, so the fleet MPG now comes from truck 1 alone. That is correct, because MPG is total miles divided by total gallons, and a parked truck has neither. If you sell a truck, or take it off the road for good, ask your base State what to do with its decals. The IFTA license guide covers that change.

Now take the harder case. Say both trucks had sat all quarter while you waited out a slow winter. Many owners think a quarter with no miles needs no return. It does. West Virginia’s return has a box to mark if you did not operate. Its instructions say the return “must be filed regardless of activity” (the West Virginia return instructions). Filing it late can still cost you. The penalty rule sets a floor of $50, even when no tax is due (the rule on penalties).

Watch the pattern too. Say your trucks report zero miles, or miles only in your base State, for three quarters or more in a row. Then your State can cancel your license or refuse to renew it. To license you again, it can ask for proof that you really run in other States (the rule on renewal). If your trucks rarely leave West Virginia, ask whether you need IFTA at all. The rulebook lets an owner buy a trip permit for each trip instead of holding a license.

There is one more choice for a year with little travel outside your base State. Say your trucks drove less than 5,000 miles outside your base State over 12 months in a row. Then you can ask your base State to let you file once a year instead of each quarter. The yearly return is due January 31. Your State must approve it first (the rule on yearly filing).

Chapter 06

What if I find a mistake after I filed?

File an amended return for that quarter with your base State, as soon as you find the mistake. Owners search for this as an IFTA amended return. The rulebook leaves the steps to each State. West Virginia’s return has a box to mark it as amended (the West Virginia return instructions). If the fix means you owe more, you pay the difference with interest from the first due date. If it means you paid too much, the difference becomes a credit.

On Monday, November 16, 2026, you look over the third quarter again. One receipt from a truck stop in Pennsylvania, for 500 gallons, was typed in as West Virginia. So West Virginia got 500 tax paid gallons it should not have, and Pennsylvania missed them.

Work it through with the same rates we made up. West Virginia’s credit shrinks by 500 gallons at $0.40, which is $200. Pennsylvania’s bill shrinks by 500 gallons at $0.75, which is $375. So the fix is $175 in your favor. You mark the return as amended, enter the right numbers for the third quarter, and send it to West Virginia. The $175 becomes a credit. You can use it on your fourth quarter return, or ask for it back (the rules on credits and refunds).

Had the mistake gone the other way, you would owe money. Say a West Virginia receipt had been typed in as Pennsylvania. Then you would owe $175 more, plus interest from November 2. Your State could also add a penalty of at least $50, because the rule covers tax that was underpaid (the rule on penalties). It can waive the penalty for reasonable cause. It can waive interest only in narrow cases, such as a late return caused by wrong advice from the State itself.

Why not leave a small error alone? Because your base State audits its IFTA carriers on behalf of all the member States (the rule on audits). An auditor who finds the error works out the tax you owe, and penalty and interest can follow. What an audit looks like, and how to answer one, is in our guide to the IFTA audit.

How long do you have? IFTA’s rules set no deadline for an amended return, though your State may set one. Two other clocks do run. A credit runs out after eight quarters. And your State need not refund tax for a quarter once its records no longer have to be kept (the rules on credits and refunds). So fix a mistake as soon as you find it.

What has changed lately? Since January 1, 2026, IFTA’s rulebook measures fuel as “volume”, which also covers kilowatt hours for electric trucks. For a diesel fleet, nothing changes. The interest rate resets every January, and each State can change its tax rate from one quarter to the next. If an older booklet tells you IFTA interest is 1% a month, it is out of date. The way interest is set changed on July 1, 2013 (the rulebook’s history notes). And in August 2026, IFTA’s board ruled on fuel with no receipt. An auditor should not allow a credit for it unless you have a receipt or another required record (IFTA’s Procedures Manual).

There are also things we could not check. IFTA’s rules on this page come from the editions in force since August 26, 2026 (IFTA’s manuals page). But each State runs its own website, payments and amended returns, and we could not check all of them. IFTA also posts the rates as each State reports them, and it does not vouch for them itself. So look at the rate table again just before you file, and ask your base State if anything on its form is unclear.

IFTA is only one of the filings on your calendar. The yearly UCR registration is another, and our UCR guide walks through it. If you would rather have someone pull the miles and receipts together every quarter and file the return for you, here is what we offer.