IFTA Q1 2026 Filing Guide: Rates, Deadlines, and What Changed

Q1 2026 IFTA returns are due April 30, 2026. That covers all miles driven and fuel purchased between January 1 and March 31. If you operated qualified motor vehicles across state lines during those three months, your base jurisdiction expects a completed return — even if you owe nothing.

This quarter brings a handful of fuel tax rate changes from Q4 2025, a few states adjusting surcharges, and the usual first-quarter complications: fleet turnover at the start of the year, weather-related mileage gaps, and new vehicles that may not have a full quarter of data. This guide walks through everything you need to file accurately and on time.

In this guide, you will learn:

• The Q1 2026 filing deadline and how extensions work
• Which state fuel tax rates changed from Q4 2025 to Q1 2026
• A step-by-step walkthrough of the Q1 filing process
• Common Q1-specific mistakes and how to avoid them

Q1 2026 Deadline: April 30, 2026

IFTA quarterly returns are due on the last day of the month following the quarter's end. For Q1 (January–March), that's April 30. If April 30 falls on a weekend or holiday, the deadline shifts to the next business day. In 2026, April 30 is a Thursday, so there's no extension — the deadline stands.

Most base jurisdictions allow you to request an extension of 30 days, pushing the due date to May 30. However, extensions only extend the filing deadline — not the payment deadline. Interest begins accruing on any tax owed starting May 1 regardless of whether you filed for an extension. The interest rate varies by jurisdiction but typically ranges from 1% to 1.5% per month.

Late filing penalties also vary by state but commonly start at $50 or 10% of the tax due (whichever is greater) and increase the longer you wait. Some jurisdictions impose a flat penalty per month of delinquency. Filing a zero-due return late still incurs the minimum penalty in most states.

Rate Changes: Q4 2025 to Q1 2026

IFTA fuel tax rates can change at the start of each quarter. States update rates based on wholesale fuel prices, legislative changes, or inflation adjustments. Q1 2026 brought several notable changes. The table below summarizes the states with rate adjustments for diesel fuel.

Most changes are modest — a penny or less per gallon. But on a truck burning 5,000 gallons per quarter, even a $0.01 increase in a state where you drive significant miles translates to real money. Always use the current quarter's rate table published by IFTA Inc. when completing your return. Your base jurisdiction typically provides an updated rate sheet, and the official IFTA rate tables are available at ifta.org.

Important: You must use Q1 2026 rates for the entire Q1 return, even if you filed a trip in January when Q4 2025 rates were technically still displayed on some state websites. The rate that applies is the rate for the quarter being reported, not the date the trip occurred within a rate transition.

Step-by-Step Q1 Filing Walkthrough

Whether you file online through your base jurisdiction's portal or use IFTA software, the process follows the same logical steps. Here is how to work through your Q1 return from start to finish.

Step 1: Gather Your Records

Before you touch the return, collect all supporting data for January 1 through March 31, 2026:

• Mileage records: Trip sheets, GPS logs, or ELD data showing miles driven in each state
• Fuel receipts: Every fuel purchase with date, location (state), gallons, and total cost
• Vehicle list: All qualified motor vehicles that operated during Q1, including any added or removed mid-quarter
• Odometer readings: Beginning and ending odometer for each vehicle for the quarter

If you use a fleet card, download the quarterly fuel transaction report. Match it against any cash or non-fleet-card purchases your drivers made. Missing even a few fuel stops means unclaimed credits.

Step 2: Calculate Total Miles by State

Add up every mile driven in each IFTA jurisdiction during Q1. This includes both loaded and empty miles. Toll records, GPS data, and trip sheets should all reconcile. If you have discrepancies between data sources, resolve them before filing — auditors will compare these same sources.

Don't forget: miles driven in your home state count too. A common mistake for single-state-heavy carriers is underreporting home-state miles because they think IFTA only covers "other" states.

Step 3: Calculate Total Fuel by State

Tally gallons purchased in each jurisdiction. Use actual receipt data, not estimates. Every gallon you purchased and can document becomes a tax credit in that state. Bulk fuel from your own tanks counts too, but you need proper documentation — purchase invoices for the bulk fuel and a log showing how much was dispensed to each vehicle.

Step 4: Determine Fleet MPG

Divide total miles driven (all jurisdictions combined) by total gallons consumed (all jurisdictions combined). This gives you your fleet average MPG. Most carriers use fleet-wide MPG rather than per-vehicle MPG, though per-vehicle is allowed and sometimes advantageous for mixed fleets.

Example: 120,000 total miles ÷ 20,000 total gallons = 6.0 MPG

If your calculated MPG falls below 4.0 or above 8.0 for Class 8 diesel trucks, double-check your numbers. Auditors flag returns with unusual MPG figures, and a data-entry error here throws off every state's calculation.

Step 5: Complete the Return

For each jurisdiction, the return calculates:

1. Taxable gallons consumed = Miles in state ÷ fleet MPG
2. Tax-paid gallons = Gallons actually purchased in that state
3. Net taxable gallons = Taxable gallons − tax-paid gallons
4. Tax due (or credit) = Net taxable gallons × state tax rate

Sum all jurisdictions. If the total is positive, you owe money. If negative, you're due a refund. Submit the return through your base jurisdiction's portal or mail the paper form with payment.

Step 6: Submit and Pay

Most jurisdictions now accept (and prefer) electronic filing and payment. E-filing confirmation is immediate, and electronic payment eliminates mail delays that can cause late-payment penalties. Keep a copy of your confirmation number and payment receipt.

Common Q1-Specific Mistakes

Q1 has some unique pitfalls that don't apply to other quarters. Watch for these:

Weather-Related Mileage Gaps

Winter storms in Q1 cause trucks to sit idle for days. Drivers may skip trip sheet entries during downtime, creating gaps in your mileage records. When you later tally state miles, those gaps look suspicious — especially if fuel purchases don't align with mileage for the period. Log idle days with zero-mile entries so your records show continuous coverage.

New Year Fleet Changes

Many carriers add or remove vehicles at the start of the year. New trucks added in January need IFTA decals before operating interstate. If a driver ran trips in a new vehicle before decals were obtained, those miles still need to be reported. Conversely, vehicles sold or retired in Q1 should have final odometer readings recorded and their Q1 miles included in the return.

Using Last Quarter's Rates

If you prepare your return manually or with spreadsheets, it's easy to accidentally carry forward Q4 2025 rates into Q1 2026. Always verify you're using the published Q1 2026 rate table. Even small rate differences, compounded across multiple states, can result in an underpayment that triggers a balance-due notice.

Forgetting Partial-Quarter Vehicles

A truck that only operated for two weeks in January before being sold still needs its Q1 miles and fuel reported. Some carriers accidentally omit vehicles that weren't active for the full quarter, underreporting both miles and fuel.

Non-Receipted Fuel

Cash fuel purchases in Q1 — especially during bad weather when drivers stop at unfamiliar stations — sometimes lack proper receipts. IFTA requires receipts to claim fuel credits. A credit card statement alone is not sufficient; you need the receipt showing gallons, price per gallon, date, and location. Train drivers to photograph every receipt immediately, regardless of payment method.

What Happens If You Don't File

Missing the April 30 deadline has cascading consequences. Your base jurisdiction will assess late penalties and interest. If you remain delinquent, they can revoke your IFTA license, which means your trucks can no longer legally operate interstate. Reinstatement requires paying all back taxes, penalties, and interest — plus a reinstatement fee in most jurisdictions.

Even if you had zero operations in Q1, you must file a zero return unless you surrendered your IFTA credentials before the quarter started. Active IFTA accounts require a return every quarter, period.

Frequently Asked Questions

Can I get an extension on the Q1 2026 filing deadline?

Most base jurisdictions allow a 30-day extension for filing, pushing the deadline to May 30, 2026. However, you must request the extension before April 30, and interest on any tax owed still begins on May 1. Extensions do not extend the payment deadline — only the paperwork deadline.

What if I only operated in one state during Q1?

If you only operated within your base jurisdiction (no interstate travel), you technically don't need to file an IFTA return for that quarter. However, if you hold an active IFTA license, most jurisdictions still expect a return showing single-state operations. Check with your base jurisdiction, as policies vary.

Do I report Canadian provinces on my Q1 return?

Yes. If you drove in any Canadian IFTA member province during Q1, those miles and fuel purchases must be included on your return. All 10 Canadian provinces participate in IFTA. Use the published Q1 2026 Canadian rates, which are listed in Canadian dollars on the IFTA rate table.

My fleet MPG seems too low. Should I still file with it?

File with your actual calculated MPG, but investigate the cause before submitting. Common causes of low MPG include fuel theft, unreported fuel purchases (inflating the denominator), or underreported miles. If you can't find the discrepancy, file with the calculated MPG and document your investigation. Filing with an artificially inflated MPG to reduce tax owed is fraud.

What records do I need to keep after filing?

IFTA requires you to retain all supporting records for four years after the filing date or due date, whichever is later. That includes trip sheets, GPS logs, fuel receipts, odometer readings, and a copy of the filed return. If you're audited, the auditor can request records going back the full four years.

Bottom Line

Q1 2026 has a clean April 30 deadline with no holiday extensions. Rates changed in a handful of states, so make sure your calculations use the current quarter's table. Watch for the typical first-quarter traps — weather gaps, new vehicles, and leftover Q4 rates in your spreadsheets. If your fleet tracks miles and fuel electronically, most of the heavy lifting is already done. Tools like FleetCollect automate state mileage tracking via GPS and generate the data you need for a clean quarterly filing, saving you the manual reconciliation that causes most Q1 errors.