How to Fill Out an IFTA Quarterly Return (Step by Step)

Every quarter, owner-operators running under IFTA owe a fuel tax return to their base state — one return that covers every state and Canadian province where they ran miles. The concept is straightforward: you pay fuel taxes where you buy fuel, but fuel tax is owed where you burn it. IFTA reconciles the difference.

The math isn't complicated, but the data preparation trips most people up. Here's how to do it right.

What IFTA actually does

Without IFTA, you'd owe separate fuel tax filings to every state where you drove. IFTA consolidates all of it into one return filed with your base jurisdiction. You report miles and fuel by state, calculate what you owe each jurisdiction, and either pay the net amount or receive a credit — all through your base state.

If you bought most of your fuel in cheap-tax states but burned most of it in high-tax states (common on long east-west runs), you'll owe the difference. If you fueled up heavily in high-tax states and burned it in low-tax states, you'll typically get a credit.

What you need before you start

Gather all of this before you open the return. Missing data mid-calculation leads to errors:

Miles by jurisdiction:

• Total miles driven in each state or province during the quarter
• Separate numbers for loaded and unloaded miles (some states want this, all require total)
• Trip records, ELD data, or a mileage log by state

Fuel purchases by jurisdiction:

• Gallons purchased in each state or province
• Fuel receipts that show date, location (state), gallons, cost, and vehicle
• Keep receipts even if you paid with a fuel card — the card statement isn't the receipt for audit purposes

Your IFTA license and decal numbers

The current quarter's tax rates by state — IFTA, Inc. publishes these quarterly. Your base state's IFTA agency also posts them. Rates change every quarter, so don't use last quarter's numbers.

Step 1: Calculate your fleet MPG

IFTA uses a single average MPG across your fleet (or just your truck if you're a one-truck operation) for the quarter. The formula:

Total miles traveled ÷ Total gallons purchased = Fleet MPG

Example: Say you ran 28,000 miles and purchased 4,000 gallons. That's 7.0 MPG.

This number applies uniformly across all jurisdictions. You don't recalculate MPG by state — one fleet MPG for the whole return.

Step 2: Calculate taxable gallons by jurisdiction

For each jurisdiction where you ran miles, calculate how many gallons were "consumed" there based on your fleet MPG:

Miles in jurisdiction ÷ Fleet MPG = Taxable gallons for that jurisdiction

Example: If you ran 3,200 miles in Texas and your fleet MPG is 7.0, your taxable gallons in Texas are 457.1 (3,200 ÷ 7.0).

Do this for every state and province where you ran miles during the quarter.

Step 3: Calculate net taxable gallons by jurisdiction

You already paid fuel tax when you bought fuel. IFTA credits you for that.

Taxable gallons (Step 2) − Gallons purchased in that jurisdiction = Net taxable gallons

If the number is positive: you owe fuel tax for those gallons in that jurisdiction. If the number is negative: you already overpaid fuel tax in that jurisdiction (bought more fuel there than you burned there), and you get a credit.

Example continuing from above:

• Texas taxable gallons: 457.1
• Gallons purchased in Texas: 200
• Net taxable gallons: 257.1 (you owe tax on 257.1 gallons in Texas)

Or if you'd bought 600 gallons in Texas: net would be −142.9 (credit of 142.9 gallons).

Step 4: Apply the tax rate

Multiply net taxable gallons by the jurisdiction's fuel tax rate for the quarter.

Net taxable gallons × Jurisdiction tax rate = Tax owed (or credit)

For states where the result is positive, that's tax you owe them. For states where it's negative, that's a credit that offsets your total balance.

IFTA rates are per-gallon amounts set by each jurisdiction, updated quarterly. They vary — some states are meaningfully higher than others, which is why cross-country runners often see credits in low-tax states and balances due in high-tax states.

Step 5: Sum across all jurisdictions

Add up all the positive tax amounts and all the negative credit amounts across every jurisdiction on your return.

• If the net total is positive: you owe that amount to your base state, which distributes it to the appropriate jurisdictions on your behalf
• If the net total is negative: you have an overpayment credit; depending on your base state's rules, you can apply it to next quarter or request a refund

Step 6: File with your base state

Your base state's IFTA agency sets the actual filing process. Most states offer online filing; some still accept paper returns. Quarterly returns are typically due:

If the deadline falls on a weekend or holiday, most states extend to the next business day — but don't count on it. File before the deadline, not on it.

Late returns come with penalties and interest charges that vary by state. Missing IFTA entirely is worse — it's an audit trigger and can result in larger penalties plus back taxes.

The data problem most owner-operators run into

The math in Steps 1–6 is manageable. The hard part is having accurate miles-by-state data at the end of the quarter.

ELD systems record where your truck physically is, which is the foundation for miles-by-state. But converting that into a clean state-by-state mileage log still requires work if you're doing it manually — pulling logs, tallying border crossings, reconciling with trip sheets.

Automatic state mileage tracking via ELD integration (Motive and Samsara sync directly into Truck Command) handles this automatically during the quarter, so when Q1 closes you have a state-by-state mileage breakdown ready rather than rebuilding it from records. The IFTA calculator then applies current tax rates to produce the return.

The difference between doing IFTA with good data versus reconstructed data is usually a weekend of your time — or worse, an error on the return.

What to keep for audit purposes

IFTA audits happen. Keep these records for at least four years (some states require longer — check your base state's rules):

• Fuel receipts or fuel card statements that show location, date, gallons, and vehicle
• Mileage records or trip reports that show odometer readings or GPS-based mileage by state
• Driver logs or ELD records
• Your quarterly IFTA returns

If you're audited and can't produce fuel receipts by state with the required information, the auditor may disallow those purchases and recalculate your tax — usually not in your favor.

Common mistakes on IFTA returns

• Using loaded miles only. IFTA requires total miles — loaded and unloaded. Deadhead and bobtail miles count.
• Missing jurisdictions. If you drove through a state even briefly (pickup, delivery, or transit), you need to include it. A few hundred miles in a state you forgot is an audit finding.
• Using last quarter's tax rates. Rates change quarterly. Always use the current-quarter rates.
• Not keeping fuel receipts. Card statements alone aren't sufficient for audit purposes in most states. You need the actual receipt showing the information.
• Filing late. Even a few days late triggers penalties in most states.

How Truck Command makes IFTA filing faster

Truck Command tracks fuel purchases by state as you log them through fuel tracking, syncs state mileage from your ELD, and generates your quarterly IFTA calculation with current tax rates. By the time the quarter ends, the return data is already there.

Plans start at $20/month. The 14-day free trial (no credit card required) covers a full quarter's worth of fuel and mileage tracking — import your existing data or start fresh and see what automated IFTA prep looks like before your next filing.

The goal is to know exactly what you owe before you file, not to discover surprises when the return is due.