Q4 2026 IFTA diesel rate
Connecticut IFTA fuel tax rate, Q4 2026
CTConnecticut · diesel$0.4990/gal
Unchanged from Q3 2026.
Checked 2026-10-14 against portal.ct.gov, Connecticut's own published rate.
Calculate Connecticut for Q4 2026Free. No account.
What you owe Connecticut
IFTA apportions your fuel by miles. Divide total miles by total gallons for fleet MPG, turn your Connecticut miles into taxable gallons, subtract the tax-paid gallons you bought in Connecticut, and multiply by $0.4990.
Example: 1,000 miles in Connecticut at 6.5 MPG is 153.85 taxable gallons. With 100 tax-paid gallons bought there, 53.85 × $0.4990 = $26.87 owed to Connecticut.
This rate is for diesel, Q4 2026. You still file with your base jurisdiction; keep your trip records and receipts.