IFTA Diesel Tax Rates by State 2026: Complete Jurisdiction Guide

Every quarter, trucking companies across North America sit down to file their IFTA returns. The single biggest variable in that calculation? State diesel tax rates. These rates determine whether you owe money or get a refund for each jurisdiction you drove through. For Q1 2026, rates range from $0.180 per gallon in Mississippi all the way up to $1.090 in California — a difference of over $0.90 per gallon that can swing your bottom line by thousands of dollars per quarter.

US IFTA Diesel Tax Rates — Q1 2026

The table below lists all 48 contiguous states plus the District of Columbia. Alaska and Hawaii are also IFTA members. Rates shown are the combined state and federal diesel fuel tax per gallon.

Rates shown are Q1 2026 combined state + federal diesel tax rates as published by IFTA, Inc. Rates may change quarterly. Always verify current rates at iftach.org before filing.

Canadian Provincial Diesel Tax Rates — Q1 2026

All 10 Canadian provinces participate in IFTA. Rates below are in Canadian dollars per liter (not per gallon). When filing your IFTA return with a US base jurisdiction, your state will handle the conversion.

Canadian rates are in CAD per liter. 1 US gallon = 3.785 liters. Canadian territories (Yukon, Northwest Territories, Nunavut) do not participate in IFTA.

How IFTA Tax Rates Work

IFTA exists to simplify fuel tax reporting for carriers that operate in multiple states and provinces. Instead of buying fuel permits for every jurisdiction you enter, you file a single quarterly return with your base jurisdiction. That return calculates the net tax you owe (or are owed) for each state based on two things: how many miles you drove there and how much fuel you bought there.

The core formula is straightforward. For each jurisdiction, you divide your miles driven by your fleet's average MPG to calculate taxable gallons — the amount of fuel you theoretically consumed in that state. Then you multiply those taxable gallons by the state's tax rate to get the gross tax liability. Finally, you subtract the tax you already paid at the pump on fuel purchased in that state (fuel tax credits). The result is either a net amount due or a refund.

In formula form: Net Tax = (Miles in State / Fleet MPG x State Tax Rate) - Tax Paid on Fuel in State. This calculation is performed for every jurisdiction where you drove or bought fuel during the quarter, and the results are summed to determine your total payment or refund.

Highest and Lowest Rate States

The difference between the most and least expensive states is dramatic. Understanding these extremes helps you anticipate your IFTA liability and make smarter fueling decisions.

How Rates Affect Your IFTA Refund

Your IFTA refund or balance due comes down to a simple principle: where you buy fuel versus where you drive. The tax rate for each state is the lever that amplifies or reduces the impact.

If you buy most of your fuel in high-tax states like Pennsylvania ($0.741) or California ($1.090) but drive the majority of your miles in low-tax states like Texas ($0.200) or Oklahoma ($0.190), you are paying more tax at the pump than you owe based on miles driven. IFTA settles the difference, and you get a refund. This is the most common scenario for carriers running east-to-west routes who fill up in the Northeast.

The reverse is also true. If you fuel up cheaply in low-tax states and rack up miles in high-tax states, you will owe additional tax on your quarterly return. Carriers running heavy miles in Pennsylvania, Illinois, or California who avoid fueling in those states will see larger balances due.

Smart fleet managers consider IFTA rates when planning fuel stops. While you should never go out of your way just for a lower tax rate (the cost of deadhead miles outweighs the tax savings), choosing between two nearby fuel stops in different states can make a real difference over the course of a quarter.

When Do IFTA Rates Change?

IFTA tax rates can change at the beginning of each calendar quarter. IFTA, Inc. publishes updated rate tables before each period takes effect:

• Q1 (January 1 - March 31) — Rates published in late December
• Q2 (April 1 - June 30) — Rates published in late March
• Q3 (July 1 - September 30) — Rates published in late June
• Q4 (October 1 - December 31) — Rates published in late September

Not every state changes its rate every quarter. Many states adjust rates once per year (often on July 1), while others tie rates to fuel price indices that fluctuate quarterly. Pennsylvania, for example, recalculates its rate based on the average wholesale price of diesel, which is why it frequently has one of the highest rates in the country.

The key takeaway: always use the rates for the quarter you are filing, not the current quarter. If you are filing your Q1 2026 return in April 2026, use the Q1 2026 rates even though Q2 2026 rates are now in effect.

How to Use These Rates: A Worked Example

Let's walk through a real example. Say your truck drove 2,000 miles in Pennsylvania and 3,000 miles in Texas during Q1 2026. You purchased 600 gallons of diesel in Pennsylvania and no fuel in Texas. Your fleet average is 6.0 MPG.

This example shows why buying fuel in high-tax states can actually work in your favor. The 600 gallons purchased in PA generated $444.60 in credits, but you only consumed 333.33 taxable gallons there — the excess credit offsets your liability in Texas and produces a net refund.

Frequently Asked Questions