Base rate
$0.2200
Special diesel, per gallon, 4Q2026.
Surcharge
$0.1050
Owed on fuel burned here whatever you bought.
Total
$0.3250
Rank 23 of the 47 states with a rate.
Per mile
5.42c
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. Kentucky is below that average by $0.0431.
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 Kentucky 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 Kentucky | Taxable gallons | Owed if you buy no fuel here |
|---|---|---|
| 100 | 16.7 | $5.42 |
| 250 | 41.7 | $13.54 |
| 500 | 83.3 | $27.08 |
| 1,000 | 166.7 | $54.17 |
| 2,500 | 416.7 | $135.42 |
That 500-mile pass costs $27.08 in Kentucky 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.
The surcharge
Kentucky charges a $0.1050 surcharge on top of the base rate, and it works differently from the rate. The base rate can be settled at the pump: buy your fuel here and you have already paid it. The surcharge cannot. It is assessed on every gallon you BURN in Kentucky no matter where you bought it, so it can only ever arrive as a balance due on the return.
At 6.0 mpg that is 1.75 cents on every mile you run here that no fuel purchase will ever offset. It is the most common reason a return that looked settled comes back owing money.
Source: IFTA, Inc. Tax Rate Matrix. Special diesel rate for 4Q2026. Rates are reset every quarter. Read 2026-09-15.