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IFTA Fuel Tax Calculator — Quarterly Fuel Tax by Jurisdiction

Calculate your IFTA quarterly fuel tax liability. Enter miles driven and fuel purchased by jurisdiction to determine what you owe — or what refund you're owed.

Quick answer: IFTA tax = Miles driven in jurisdiction ÷ Fleet MPG × Jurisdiction tax rate − Fuel purchased in jurisdiction × That state's rate. Net positive = you owe; net negative = refund.

📋 IFTA Fuel Tax Calculator

Find at iftach.org or your state DMV
Net IFTA Tax
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Fleet MPG
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Home State Net
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How to Use This Calculator

  1. Gather quarterly mileage — total miles driven in all IFTA jurisdictions from your ELD or trip records.
  2. Gather fuel receipts — total gallons purchased by state. Keep all fuel receipts — they are required for IFTA audits.
  3. Find tax rates — current IFTA tax rates by state are published quarterly at iftach.org.
  4. File with your base state — submit your IFTA return and payment by the quarterly deadline. Late filing incurs penalties.

Worked Example

A carrier drives 12,000 miles using 1,846 gallons. 4,200 miles and 900 gallons in home state (TX, $0.244/gal). 7,800 miles and 946 gallons in other states (avg $0.268/gal).

  1. Fleet MPG: 12,000 ÷ 1,846 = 6.50 MPG
  2. TX tax due: (4,200 ÷ 6.50) × $0.244 = $157.72
  3. TX tax paid: 900 × $0.244 = $219.60 → refund $61.88 from TX
  4. Other states tax due: (7,800 ÷ 6.50) × $0.268 = $321.60
  5. Other tax paid: 946 × $0.268 = $253.53 → owe $68.07
  6. Net: -$61.88 + $68.07 = owe $6.19

Frequently Asked Questions

Any motor carrier operating a qualified motor vehicle in two or more IFTA jurisdictions must file. Qualified vehicles have 3+ axles, or 2 axles with GVW over 26,000 lbs, or are used in combination with a GVW over 26,000 lbs. Vehicles operating only in one jurisdiction are exempt.

IFTA returns are filed quarterly: Q1 (Jan–Mar) due April 30, Q2 (Apr–Jun) due July 31, Q3 (Jul–Sep) due October 31, Q4 (Oct–Dec) due January 31. Late filing incurs a penalty of $50 or 10% of net tax due, whichever is greater.

Keep fuel receipts (showing date, location, gallons, vehicle ID), mileage records by jurisdiction (trip sheets or ELD reports), and depreciation records for at least 4 years. ELD data satisfies most mileage record requirements.