IFTA fuel tax calculator
An IFTA return charges you fuel tax for the miles you drove in each state, then credits the tax you already paid at the pump there. This calculator does that math per state: miles, taxable gallons (miles ÷ fleet MPG), tax-paid gallons, net gallons and net tax.
Last reviewed · by the fleetchart team
Net tax due
$0.00
Some states with miles have no rate yet. Enter each rate from the IFTA matrix.
- State 1
- -$0.00
- State 2
- $0.00
- State 3
- $0.00
- Fleet MPG
- 6.25
- Net on the return
- $0.00
6,000 mi · 960 taxable − 1,100 paid = -140 gal
2,500 mi · 400 taxable − 300 paid = 100 gal
1,500 mi · 240 taxable − 200 paid = 40 gal
Total miles ÷ total gallons
How to read this
Start with your fleet MPG for the quarter: total miles in every state divided by total gallons used. IFTA returns show it to two decimal places. Every state's taxable gallons come from that one number. Miles in a state ÷ fleet MPG = the gallons that state says you burned there.
Then subtract the gallons you bought in that state with tax already paid, as shown on your fuel receipts. The result is net taxable gallons. If it is positive, you owe that state. If it is negative, you bought more fuel there than you burned, and you get a credit. Net gallons × the state's rate = tax due or credit, and the credits offset what you owe elsewhere.
Rates change every quarter, so this calculator does not ship with any. Look each state's rate up on the IFTA tax rate matrix at iftach.org for the quarter you are filing, and type it in. Use the rate for your fuel type (most trucks: special diesel). Kentucky and Virginia list a separate surcharge row on the matrix; this calculator doesn't model surcharges, so check those states' own instructions.
This is a planning aid, not a filing. Your return is filed with your base jurisdiction, and your preparer or state portal has the final say. fleetchart keeps the same worksheet for you (miles and fuel by state each quarter, with EFS or Comdata fuel imports and Motive miles), ready to hand to your preparer. It does not file the return.
Worked example
One truck, one quarter, three states
A truck runs 10,000 miles in the quarter and buys 1,600 gallons of diesel. Rates are the 4Q 2026 special diesel rates from the IFTA matrix, used for illustration only; look up the quarter you are filing.
| State | Miles | Taxable gal | Tax-paid gal | Net gal | Rate | Tax |
|---|---|---|---|---|---|---|
| Texas | 6,000 | 960 | 1,100 | −140 | $0.2000 | −$28.00 |
| Tennessee | 2,500 | 400 | 300 | 100 | $0.2700 | $27.00 |
| Georgia | 1,500 | 240 | 200 | 40 | $0.3730 | $14.92 |
- Fleet MPG = 10,000 miles ÷ 1,600 gallons = 6.25.
- Taxable gallons = miles in each state ÷ 6.25. Texas 6,000 ÷ 6.25 = 960.
- Net gallons = taxable − tax-paid. Texas 960 − 1,100 = −140, a credit.
- Tax = net gallons × rate. Texas −140 × $0.20 = −$28.00. Tennessee 100 × $0.27 = $27.00. Georgia 40 × $0.373 = $14.92.
Net due on the return: −$28.00 + $27.00 + $14.92 = $13.92. Buying most of the fuel in Texas covered most of the tax owed to Tennessee and Georgia.
Questions
- Where do I get the current IFTA tax rates?
- From the IFTA tax rate matrix published by IFTA, Inc. at iftach.org. It lists every member jurisdiction's rate for each fuel type, updated each quarter. Use the quarter you are filing, not today's rates if they differ.
- Who has to file IFTA?
- Carriers running qualified motor vehicles across more than one member jurisdiction. Under the IFTA Articles of Agreement, a qualified motor vehicle has two axles and a gross or registered weight over 26,000 pounds, or three or more axles regardless of weight, or is used in a combination over 26,000 pounds. Recreational vehicles are excluded.
- When is the IFTA return due?
- The last day of the month after the quarter ends: April 30, July 31, October 31 and January 31. If that day is a Saturday, Sunday or legal holiday, the due date moves to the next business day. A return is required even for a quarter with no miles.
- Why do I owe tax in one state and get a credit in another?
- Because where you buy fuel and where you burn it rarely match. Fill up in a low-tax state and drive through a high-tax one, and you owe the high-tax state the difference. Credits in one state offset what you owe in another on the same return.
- What if I lose fuel receipts?
- A lost receipt doesn't lower what you owe. It removes the tax-paid credit you would have claimed, so you pay that tax twice. IFTA's rules also require you to keep fuel and mileage records for four years from the return's due date or filing date, whichever is later.
- Does fleetchart file my IFTA return?
- No. fleetchart builds the IFTA worksheet (miles and fuel by state for the quarter) and flags things that look off, like fuel bought in a state with no miles. You or your preparer file the return.
Sources
- IFTA, Inc., IFTA Tax Rate Matrix · Current quarterly fuel tax rates for every IFTA jurisdiction, including the 4Q 2026 special diesel rates quoted here. (checked )
- IFTA, Inc., Articles of Agreement (revised August 2026) · Definitions of base jurisdiction (R212) and qualified motor vehicle (R245), quarterly reporting (R930), the due date (R960) and tax-paid credits (R1010). (checked )
- IFTA, Inc., Procedures Manual (revised August 2026) · What a return reports per jurisdiction (P710, P720), fleet MPG to two decimal places, and the four-year record retention rule. (checked )
Terms used here
Stop re-typing these numbers.
A calculator answers the question once. fleetchart reads your rate confirmations and holds your expenses against the loads that caused them, so the answer stays current every week.