Idaho diesel prices and fuel tax

The four numbers add up. State excise $0.3200 plus other state fees $0.0100 gives a state total of $0.3300. Add the federal $0.2440 and the all-in figure is $0.5740 a gallon.

Every figure is rounded to four decimal places of a dollar before it is shown, and the totals are the sum of the rounded figures rather than of the unrounded ones. On three states those two differ by one ten-thousandth of a dollar. We print the sum that matches the numbers you can see, because a page that shows its arithmetic should have arithmetic that checks out.

Under IFTA, a US-licensed carrier files Idaho at $0.3200 a gallon for diesel. That is the rate the state collects on a gallon sold there, and it is a different number from the statutory total above because IFTA and the statute do not measure the same thing.

The two figures above answer different questions. The statutory excise is what Idaho levies on a gallon of diesel sold in the state. The IFTA rate is what a carrier reports to Idaho for a gallon burned there, and in most jurisdictions the two are not the same number.

The Energy Information Administration publishes a weekly on-highway diesel price on a district basis, not a state basis. There are ten districts in the whole country and Idaho is not one of them.

Idaho sits in the Rocky Mountain (PADD 4) district. The figure at the top of this page is that district's weekly price. It is not a Idaho price, and we are not going to label it as one.

Plenty of sites will show you a Idaho diesel price. What they are showing you is the same district number they show for every neighbouring state, because the state-level number does not exist to show. If a site claims a per-state diesel price, ask it which survey it came from.