Q4 2026 IFTA diesel rate

Idaho IFTA fuel tax rate, Q4 2026

IDIdaho · diesel$0.3200/gal

Unchanged from Q3 2026.

Checked 2026-10-14 against tax.idaho.gov, Idaho's own published rate.

Calculate Idaho for Q4 2026Free. No account.

What you owe Idaho

IFTA apportions your fuel by miles. Divide total miles by total gallons for fleet MPG, turn your Idaho miles into taxable gallons, subtract the tax-paid gallons you bought in Idaho, and multiply by $0.3200.

Example: 1,000 miles in Idaho at 6.5 MPG is 153.85 taxable gallons. With 100 tax-paid gallons bought there, 53.85 × $0.3200 = $17.23 owed to Idaho.

This rate is for diesel, Q4 2026. You still file with your base jurisdiction; keep your trip records and receipts.