Illinois IFTA Fuel Tax Rate, 4th quarter 2026

Diesel, October to December 2026

$0.7380per gallon

C$0.2735 per litreSince Q3 2026: no change

Example: 1,000 miles in Illinois at 6.5 mpg burns about 154 gallons, so you owe Illinois about $113.54 in fuel tax for those miles. Tax you paid at the pump in Illinois is credited on the return.

Q3 2026 IFTA return due October 31, 2026 · Illinois

Your Q3 2026 IFTA return is due October 31, 2026

File late and the penalty is $50 or 10% of the tax owed, whichever is more, plus interest. Send us your miles and fuel records and a tax professional files it for $79.

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Illinois rates for both quarters

Fuel	Q4 2026 (now)	Q3 2026 (return due October 31, 2026)
Diesel	$0.7380C$0.2735/L	$0.7380C$0.2727/L
Gasoline	$0.6530C$0.2419/L	$0.6530C$0.2412/L

Illinois's notes on the IFTA matrix

LNG and Propane are taxed per diesel gallon equivalent (DGE) beginning July 1, 2017. LNG is taxed at the rate shown per diesel gallon equivalent (DGE), with one DGE equal to 6.06 pounds of LNG. Propane is taxed at the rate shown per diesel gallon equivalent (DGE) with one DGE equal to 6.41 pounds of propane. Multiply IL taxable and tax paid propane gallons by 0.651 to determine the DGEs subject to the Illinois rate. CNG is taxed at the rate shown per gasoline gallon equivalent (GGE), with one GGE equal to 5.66 pounds of compressed natural gas. All other fuels are taxed at the rates shown per gallon. For further information, see Informational Bulletin FY 2017-15, available on our website at tax.illinois.gov.

Diesel prices in Illinois this week Truck stops and diesel in Illinois

Source: IFTA, Inc. fuel tax rate matrix, last updated by IFTA, Inc. on 11/10/26. The 4th quarter 2026 matrix is not final until December 4, 2026. States can still send changes; see IFTA's late rate notices. Your base state's return is what counts; check its instructions before you file.

Illinois carriers: we file your IFTA return

Your 3rd quarter 2026 return is due October 31, 2026. $79 a quarter, or $300 for a full year. Fuel tax you owe is paid to your base state and isn't included.

Send your ELD miles report or trip sheets and your fuel card report or receipts
A tax professional works out every state and province and files with your base state
You approve the return before it is filed and get a copy for your records
Behind on a quarter? Pick every quarter you missed on the form

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Common questions

What is the Illinois IFTA diesel tax rate for the 4th quarter 2026?

$0.7380 per gallon, for fuel used October to December 2026. It is the same as in Q3 2026.

What Illinois rate goes on my 3rd quarter 2026 return?

$0.7380 per gallon for diesel. That return covers July to September 2026 and is due October 31, 2026.

What is a surcharge line?

Some states (for example Kentucky and Virginia) add a separate surcharge on fuel used in their state. It is listed as its own line on the IFTA matrix and on the return. The diesel totals on these pages add the surcharge to the base rate.

Why are Canadian rates shown per litre and in two currencies?

IFTA lists every rate both in U.S. dollars per U.S. gallon and in Canadian dollars per litre, using one exchange rate per quarter. A U.S.-based carrier files in gallons and U.S. dollars; a Canadian-based carrier files in litres and Canadian dollars.

Do I owe tax twice if I buy fuel in one state and drive in another?

No. You owe each state tax on the fuel you burned there (miles there ÷ your fleet MPG × that state's rate). The tax you already paid at the pump is credited. The IFTA return adds it up: you pay the states you under-paid and get credit from the ones you over-paid.