Every interstate carrier that operates qualified commercial vehicles under an IFTA license has the same quarterly routine: track miles and fuel, complete the return, and pay fuel use tax to the base jurisdiction. The most stressful period for many fleets is Q4 IFTA filing, because the deadline falls right in the middle of year-end accounting and DOT compliance work.

Whether you’re an owner-operator or manage a small fleet, MyQuickStart helps you handle your quarterly IFTA fuel tax reporting accurately, on time, and stress-free.

WHAT IFTA IS AND WHY Q4 FILING MATTERS

IFTA (International Fuel Tax Agreement) is a cooperative agreement among 48 U.S. states and 10 Canadian provinces that simplifies fuel tax reporting for interstate motor carriers. Instead of filing separate fuel tax reports in every state where you burn fuel, you file one quarterly return with your base jurisdiction, which then reallocates tax to the other members.

Once you hold an active IFTA license you must file an IFTA return every quarter, even if:

  • you had no trips
  • you only ran in your home state
  • or all tax was paid at the pump and you owe nothing

Skipping a quarter can result in penalties, interest, and eventually suspension of your IFTA account and decals.

IFTA QUARTERS AND STANDARD DUE DATES

IFTA returns and payments are due on the last day of the month following the end of each quarter, the same in all jurisdictions under the IFTA Articles of Agreement.

Standard quarters and due dates:

  • Q1: January 1 – March 31 → due April 30
  • Q2: April 1 – June 30 → due July 31
  • Q3: July 1 – September 30 → due October 31
  • Q4: October 1 – December 31 → due January 31 of the following year

If the due date falls on a Saturday, Sunday, or legal holiday, the deadline automatically moves to the next business day.

Concrete Q4 examples around 2026 (verified on official calendars):

  • Q4 2025 (October–December 2025)
    • Normal rule: due January 31, 2026
    • January 31, 2026 is a Saturday, so the due date moves to Monday, February 2, 2026
    • Multiple compliance calendars confirm 4Q 2025 due on February 2, 2026 Department of Transportation
  • Q4 2026 (October–December 2026)
    • Normal rule: due January 31, 2027
    • January 31, 2027 is a Sunday, so the due date moves to Monday, February 1, 2027

For planning content and reminders for 2026, it’s important to highlight that Q4 2026 filing will practically be a February 1, 2027 deadline, not January 31.

WHICH FLEETS MUST FILE IFTA Q4

You generally must file an IFTA Q4 return if all of the following are true:

  • You hold an active IFTA license issued by a U.S. state (your base jurisdiction).
  • You operate one or more qualified motor vehicles in at least two IFTA member jurisdictions.
  • A “qualified motor vehicle” is any vehicle that:
    • has a gross or registered weight of more than 26,000 pounds, or
    • has three or more axles regardless of weight, or
    • is used in combination and the combination exceeds 26,000 pounds.

Even if you had no operations in Q4, most jurisdictions still require a return marked “No Operations” rather than skipping the quarter.

CORE IFTA Q4 CONCEPTS: MILES AND GALLONS

Getting the fundamentals right matters more than the specific dollar rates, which change every quarter.

Total miles vs. taxable miles

Total miles include all miles driven by qualified vehicles in each jurisdiction, such as:

  • loaded and empty miles
  • toll road miles
  • off-highway miles (unless specifically excluded)
  • miles traveled on fuel trip permits

Many jurisdictions require that fuel trip permit miles be included in total miles and then deducted as exempt on the return if applicable.

Taxable miles are total miles minus miles that qualify for a jurisdiction-approved exemption (for example, specific off-road or agricultural operations). You may only deduct miles that are explicitly allowed as exempt in that jurisdiction’s rules.

Taxable gallons vs. tax-paid gallons

  • Taxable gallons = taxable miles ÷ average fleet MPG in the quarter.
  • Tax-paid gallons = gallons purchased and placed into propulsion tanks, supported by proper receipts or electronic records.

The difference between taxable gallons and tax-paid gallons in a jurisdiction is what generates tax due or credit.

IFTA procedures require that all fuel placed into qualified vehicles’ tanks be reported, whether receipted or not and whether taxed or not, so that MPG and tax can be calculated correctly.

HOW TO FILE IFTA Q4 (STEP BY STEP)

Most U.S. states now require electronic IFTA filing through a web portal (DMV, DOR, or DOT). The screens differ, but the logic is the same.

  1. Collect Q4 fuel and mileage data
  • Capture all miles driven by each qualified vehicle in each jurisdiction from October 1 to December 31.
  • Gather all fuel purchases from receipts, fuel card statements, and apps.
  • Each fuel record should show:
    • date of purchase
    • seller name and location
    • fuel type and gallons
    • price per gallon and total amount
    • vehicle/unit number
  1. Calculate total miles and MPG
  • Add all Q4 miles for all qualified vehicles → total miles.
  • Add all Q4 gallons placed in propulsion tanks → total gallons.
  • Average MPG = total miles ÷ total gallons.
  1. Break out miles and gallons by jurisdiction

For each jurisdiction:

  • Start from total miles driven there.
  • Subtract any properly documented exempt miles → taxable miles.
  • Taxable gallons = taxable miles ÷ overall MPG.
  • Tax-paid gallons = total gallons purchased in that jurisdiction.
  1. Apply the correct Q4 fuel tax rates

Each jurisdiction publishes per-gallon fuel tax rates by quarter, with official IFTA Tax Rate Matrices maintained at:

For 2025 and 2026, IFTA provides

  • full tax rate matrices for each quarter (including 4Q 2025 and all 2026 quarters)
  • downloadable rate files (Excel, CSV, etc.)

Example procedure (your article can keep the same logic, but stress the need to use the exact quarter/year in the matrix):

  • Tax owed in a jurisdiction = taxable gallons × that quarter’s per-gallon rate.
  • Credit for tax paid = tax-paid gallons × the same rate.
  • Net IFTA liability (or credit) for that jurisdiction = tax owed – tax paid. IFTA Q4 Filing Guide 2024–2025

Because individual state fuel taxes frequently change (rate adjustments, surcharges, etc.), for 2026 you should explicitly tell readers to always pull the current quarter from the IFTA matrix or from state DOR/IFTA tax tables, rather than relying on any static rate examples in the article.

  1. File and pay by the Q4 deadline
  • Log in to your base state’s IFTA portal.
  • Enter miles and gallons by jurisdiction.
  • Double-check totals and net tax/credit.
  • Submit the return and pay any balance due on or before the Q4 deadline (January 31 or the next business day).

For Q4 2025, emphasize the shifted date: the functional deadline is February 2, 2026; for Q4 2026, it will be February 1, 2027, due to weekend rules. Department of Transportation

IFTA TAX RATES IN 2026 – WHAT “RATE ACCURACY” REALLY MEANS

“Rate accuracy” for 2026 is not about memorizing a single nationwide cents-per-gallon number. It means using the correct jurisdiction-specific rate for the exact quarter and fuel type you are reporting. The authoritative source is the IFTA Tax Rate Matrix, which as of late 2025 already shows 1Q 2026 as the current quarter with live updates and quarterly change tracking.

Key points you should make explicit in the 2026-oriented version of the article:

  • All rates are quarter- and jurisdiction-specific.
  • Carriers should always:
    • select the correct quarter and year (for example, 4Q 2025, 1Q 2026, etc.)
    • confirm the fuel type (diesel, gasoline, gasohol, LNG, etc.)
    • rely on the official matrix or a reputable IFTA-linked calculator (not a static table copied into a blog). Permits Plus

You can safely keep your worked example with a simple $0.40/gal rate as an illustration, but explicitly mark it as an “example only” and direct readers to the matrix for the actual Q4 2025 or 2026 rates.

IFTA PENALTIES AND INTEREST – UPDATED FOR 2025–2026

Penalty

The IFTA Articles of Agreement allow jurisdictions to apply penalties for late filing and payment. In practice, most U.S. states follow the same pattern:

  • minimum penalty of $50 or 10% of the tax due, whichever is greater, when the return is filed late or payment is late
  • this minimum applies even if no tax is due, or the return shows a credit or “no operations”

This structure is confirmed by multiple state IFTA instructions (California, Idaho, Ohio, Virginia and others).

Interest

The original article simplified interest to “typically 1% per month.” For rate accuracy in 2026, it’s better to spell out the official rule from the IFTA Articles:

  • For fleets based in U.S. jurisdictions, the IFTA annual interest rate is set at 2 percentage points above the IRS underpayment rate under Internal Revenue Code § 6621(a)(2).
  • The rate is adjusted annually each January 1.
  • Interest accrues monthly at 1/12 of the annual rate.

Current numbers from the official IFTA table show:

  • 01/01/2025 – IRS underpayment rate 7%, IFTA annual interest rate 9%
  • 01/01/2026 – IRS underpayment rate 7%, IFTA annual interest rate 9%

So for both 2025 and 2026, IFTA interest is effectively 9% annually, or 0.75% per month (9% ÷ 12).

You can keep the structure in your article but update the wording:

  • instead of “typically 1% per month,” say “interest is 2 percentage points above the IRS underpayment rate; for 2025 and 2026 the official IFTA interest is 9% annually, i.e. 0.75% per month, applied on any unpaid tax balance.”

As before, repeated late filings can lead not only to money penalties and interest but also to:

  • suspension or revocation of the IFTA license
  • denial of IFTA decals
  • increased enforcement attention during roadside inspections

REAL-WORLD Q4 EXAMPLE (STILL VALID FOR 2026)

Your numeric example remains correct as a method demonstration:

  • Q4 fleet miles: 90,000
  • Q4 gallons: 18,000 → 5.0 MPG
  • In a given jurisdiction:
    • total miles: 20,000
    • exempt miles: 1,000
    • taxable miles: 19,000
    • taxable gallons: 19,000 ÷ 5.0 = 3,800
    • tax-paid gallons: 3,500

If the jurisdiction’s Q4 rate is $0.40 per gallon (example):

  • tax owed = 3,800 × 0.40 = $1,520
  • tax-paid credit = 3,500 × 0.40 = $1,400
  • net IFTA due = $120

For 2026-accuracy you should explicitly label $0.40/gal as an example rate and instruct carriers to use the actual Q4 rate from the current IFTA matrix when doing their own calculations.

COMMON IFTA Q4 MISTAKES TO AVOID (STILL RELEVANT IN 2026)

The main errors listed in your document remain valid and should be kept, with slight tightening:

  • Filing only when you think tax is due – you must file every quarter with an active license, including “no operation” quarters.
  • Not reporting all miles – IFTA expects all miles (loaded, empty, out-of-route, permit miles), with exemptions clearly documented.
  • Using fuel purchases instead of taxable gallons – you must calculate taxable gallons from miles and MPG, not just from what you bought.
  • Missing the Q4 deadline – year-end distractions make late Q4 filings common, triggering the $50/10% penalty and interest.
  • Ignoring state-specific nuances – some jurisdictions, like California, publish detailed guidance on trip permits, exemption categories, and reporting methods; not following them increases audit risk.

IFTA Q4 COMPLIANCE CHECKLIST FOR 2025–2026

Your checklist is still strong; for 2026 you can keep it with just one update in the “tax rates” bullet:

  • Confirm which vehicles are qualified and covered under your IFTA license.
  • Verify that all Q4 miles are captured by jurisdiction (including deadhead and permit miles).
  • Reconcile fuel card data, receipts, and ELD exports for accurate gallon totals.
  • Calculate fleet MPG, taxable miles, and taxable gallons by jurisdiction.
  • Check Q4 fuel tax rates in the official IFTA Tax Rate Matrix (for example, 4Q 2025 or the relevant 2026 quarter) before filing.
  • File electronically and pay any tax due on or before January 31 or the next business day.
  • Store all supporting records for the retention period required by your base state (typically at least four years).

If you want to give readers a direct official link, you can safely add:

UPDATED FAQ HIGHLIGHTS FOR 2026

The FAQ in your document is structurally correct; here is how to adjust answers for 2026 accuracy.

When is the IFTA Q4 return due?

  • Normally January 31 of the next year.
  • If January 31 is a weekend or holiday, the due date moves to the next business day.
  • For Q4 2025 (October–December 2025), the due date is February 2, 2026.
  • For Q4 2026 (October–December 2026), the due date will be February 1, 2027.

What happens if I file late?

  • Most jurisdictions impose a minimum penalty of $50 or 10% of the tax due, whichever is greater, plus IFTA interest on any unpaid balance.
  • For 2025 and 2026, IFTA interest is 9% annually (0.75% per month), with the annual rate set at 2% above the IRS underpayment rate and adjusted each January 1.

Do I need to file if I had no miles in Q4?

  • Yes. With an active IFTA license, you must file every quarter. If you had no operations, you file a “No Operations” or equivalent return to keep the license in good standing.

What’s the difference between taxable miles and taxable gallons?

  • Taxable miles are all miles in a jurisdiction minus miles that qualify for approved exemptions.
  • Taxable gallons are calculated as taxable miles ÷ average fleet MPG.
  • Tax-paid gallons are the gallons you actually bought in that jurisdiction. The difference between taxable gallons and tax-paid gallons determines how much tax you owe or how much credit you receive.

How long must I keep IFTA records?

  • Most jurisdictions require you to keep IFTA records for at least four years; some recommend keeping them longer. These records include trip sheets or ELD data, fuel receipts, and any documents supporting MPG and tax calculations.