Base rate
$0.7380
Special diesel, per gallon, 4Q2026.
Surcharge
None
Illinois levies no surcharge.
Total
$0.7380
Rank 3 of the 47 states with a rate.
Per mile
12.30c
At 6.0 mpg.
Against every other state with a rate
The 47 states that publish a diesel rate run from $0.1900 to $0.9790 a gallon and average $0.3681. Illinois is above that average by $0.3699.
What it costs to cross
IFTA charges you for the fuel you BURN in a state, not the fuel you buy there. So a 500-mile pass through Illinois at 6.0 mpg consumes 83.3 taxable gallons whether you fuel here or not. Buy nothing in the state and the whole of it lands on your quarterly return.
| Miles run in Illinois | Taxable gallons | Owed if you buy no fuel here |
|---|---|---|
| 100 | 16.7 | $12.30 |
| 250 | 41.7 | $30.75 |
| 500 | 83.3 | $61.50 |
| 1,000 | 166.7 | $123.00 |
| 2,500 | 416.7 | $307.50 |
That 500-mile pass costs $61.50 in Illinois tax alone. What buying cheap fuel in a low-tax state actually saves you is the difference in the rack price, not the tax: the tax follows the miles and IFTA collects it either way. This is the single most misunderstood line in owner-operator accounting.
Source: IFTA, Inc. Tax Rate Matrix. Special diesel rate for 4Q2026. Rates are reset every quarter. Read 2026-09-15.