Enter your miles and fuel purchases by state to see exactly what you owe (or are owed) for IFTA. Includes current tax rates for all 48 lower states.
Add each state you drove through this quarter.
| State | Miles | Owed | Credit | Net |
|---|---|---|---|---|
| TX | 3,200 | $98.46 | $64.00 | $34.46 |
| OK | 1,800 | $52.62 | $28.50 | $24.12 |
| AR | 1,200 | $52.62 | $22.80 | $29.82 |
| Total | 6,200 | $203.69 | $115.30 | $88.39 |
* Tax rates are approximate 2026 Q1 rates. Always verify with your IFTA filing service or state tax authority before filing.
Flintrock OS tracks your miles and fuel purchases automatically, calculates IFTA tax by state in real time, and generates filing-ready reports every quarter. No spreadsheets.
Get Early AccessEverything you need to know about the International Fuel Tax Agreement.
The International Fuel Tax Agreement (IFTA) is a tax agreement between the 48 lower US states and Canadian provinces. It simplifies fuel tax reporting for carriers operating across multiple jurisdictions. Instead of filing separately with each state, you file one quarterly return through your base jurisdiction, which redistributes the taxes owed to other states.
IFTA uses your overall fleet MPG to determine how many taxable gallons you consumed in each state. The formula: Taxable Gallons = State Miles ÷ Fleet MPG. You get tax credit for fuel purchased in each state (since you paid tax at the pump). The net for each state is: Tax Owed (taxable gallons × state rate) minus Tax Credit (gallons purchased × state rate). States where you drove a lot but bought little fuel will show tax owed; states where you fueled up heavily but drove fewer miles will show a credit.
IFTA returns are due quarterly: Q1 by April 30, Q2 by July 31, Q3 by October 31, Q4 by January 31. Late filing penalties are typically $50 or 10% of the tax due (whichever is greater), plus interest on unpaid amounts. Filing on time — even with an estimated amount — is always better than filing late.
Three strategies: (1) Buy fuel in high-tax states where you drive the most miles — you'll get a larger credit against a higher tax rate. (2) Keep accurate records — GPS miles logs and fuel receipts are your best defense in an audit. (3) Know your real MPG — an inaccurate MPG inflates or deflates your tax liability. Flintrock OS calculates your MPG automatically from fuel card data.
Related Tools
Common questions about IFTA fuel tax reporting.
For each state: Taxable Gallons = State Miles ÷ Fleet MPG. Tax Owed = Taxable Gallons × State Tax Rate. Tax Credit = Gallons Purchased in State × State Tax Rate. Net = Tax Owed − Credit. Sum all states for your quarterly total. States where you drove a lot but bought little fuel owe tax; states where you over-fueled give you a credit.
IFTA reporting is required in 48 US states (all except Alaska and Hawaii) and 10 Canadian provinces. Qualifying vehicles are those with 3 or more axles, or 2 axles with a gross vehicle weight over 26,000 lbs, operating in more than one member jurisdiction.
IFTA returns are due quarterly: Q1 by April 30, Q2 by July 31, Q3 by October 31, Q4 by January 31. Late filing penalties are typically $50 or 10% of the tax due (whichever is greater), plus interest. File on time even with estimates — late is always worse.
IFTA (International Fuel Tax Agreement) simplifies fuel tax reporting for interstate carriers. Instead of filing separately with each state, you file one quarterly return through your base jurisdiction, which redistributes taxes owed to other states. Any commercial carrier operating across state lines in qualifying vehicles must participate.
Three strategies: (1) Buy fuel in high-tax states where you drive the most miles — you get a larger credit. (2) Keep accurate mileage logs and fuel receipts for audit defense. (3) Use your real MPG — inaccurate MPG inflates or deflates your liability. State diesel tax rates range from $0.17/gal (Missouri) to $0.798/gal (California), so strategic fueling can save hundreds per quarter.