Idaho gas tax
State fuel excise · tax year 2026 · federal tax excluded
On a 20-gallon fill
$6.40
Over 500 gallons
$160
Per gallon
32.0¢
state only
Rate rank
16
1 is the highest
What Idaho charges at the pump
- Every time you fill a tank in Idaho, part of what you pay is tax the state charges on fuel. On a twenty-gallon fill it comes to $6.40. You never see it on the receipt because it is baked into the price at the pump. Across a year of ordinary driving it adds up to $160, and Idaho ranks 16 nationally on the rate behind it.
- Diesel is not punished in Idaho. A twenty-gallon diesel fill carries $6.40 of state tax against $6.40 on ordinary fuel — the same or less. Most states go the other way and charge diesel more, so this is worth knowing if you drive one.
- The headline rate is not quite the whole story in Idaho. There are separate charges on fuel too — inspection fees, environmental levies, that sort of thing — and they add $0.20 to a twenty-gallon fill on top of the main tax. Small on its own. Included in the price all the same.
- Idaho's motor fuel excise adds $6.40 to a twenty-gallon gasoline purchase and $160 across five hundred gallons, ranking 16 nationally by rate. ⚠️ Federal excise is excluded from both figures: it is identical in every state, so including it would compress the interstate differences this page exists to show. Fuel excise is levied per gallon rather than as a percentage, which means its real value erodes with inflation unless a legislature or an indexing formula moves it.
- Idaho taxes diesel at or below its gasoline rate: $6.40 per twenty gallons against $6.40. ⚠️ This is the minority arrangement nationally — most states levy a premium on diesel to recover the heavier road wear associated with the vehicles that burn it — so Idaho's structure is a genuine cost difference for freight rather than a rounding artifact.
- Idaho reports additional fuel levies apart from its principal excise — typically inspection, environmental or underground-storage charges — contributing $0.20 per twenty-gallon fill. ⚠️ These are reported separately by the state and are excluded from the headline rate on which the national rank is computed, so a like-for-like comparison against another state requires knowing whether that state folds equivalents into its main rate or reports them apart.
Your year of fuel tax
A $75,000 salary
| State fuel taxper gallon | 32¢ |
|---|---|
| Fuel tax, year | $200 |
| You must earn | $307 |
| Hours of work | 8.5 hr |
State excise only. Federal fuel tax and any local levy are not included.
Tax in a tank
A $75,000 salary
| State rate | 32¢ a gallon |
|---|---|
| Tank costs | $44.80 |
| Fifty tanks a year | $224.00 |
State excise only. The federal fuel tax and any local levy are on top of this.
Gasoline, diesel, and the charges reported separately
Per-gallon rates are shown as Idaho publishes them, to a tenth of a cent. The money columns are what those rates come to on a 20-gallon fill and across 500 gallons. Federal tax is charged on top of all of it and is not included.
| Fuel | Per gallon | On a fill | Over a year |
|---|---|---|---|
| Gasoline | 32.0¢ | $6.40 | $160 |
| Diesel | 32.0¢ | $6.40 | $160 |
| Other state charges | 1.0¢ | $0.20 | — |
What this page cannot tell you
- ⚠️ Federal fuel tax is charged on top of all this and is not included above. It is the same everywhere in the country.
- The tank and the year here are round reference amounts, not a guess at your driving. Your own total scales directly with the gallons you actually buy in Idaho.
- And some places add local fuel taxes of their own on top of the state's. Those are not counted here.
- ⚠️ Federal motor fuel excise applies in addition to every figure on this page and is deliberately excluded, being uniform nationally. Including it would raise each state's figure by the same amount and compress the differences this page exists to show.
- Quantities are reference points rather than estimates of consumption: liability is strictly proportional to gallons purchased, so any household's figure is this one scaled by its own volume. ⚠️ Fuel purchased outside Idaho is taxed by the state where it is bought, which is why the figures describe purchases rather than mileage.
- Local option fuel taxes exist in a number of states and are excluded from these figures, which cover the state levy only. Where a county or city in Idaho imposes its own charge, the true per-gallon burden at that address exceeds what this page reports.
Questions people ask
Why is there no tax line on my fuel receipt?
Because it was charged long before you got there. Fuel tax is levied per gallon on the way to the pump, so the price on the sign already contains it — nothing is added at the register, and the amount does not change with what the fuel happens to cost that week.
Is this a high-tax state for this?
Among the higher ones, yes — 16 of 51. The spread between states on this levy is wide enough that crossing a border can change the cost noticeably, which is exactly why cross-border buying is a live problem for revenue departments.
Is diesel taxed the same as gasoline?
Different rate entirely — lower than gasoline here. The split is deliberate and rests on which vehicles do most damage to the road surface.
Why does motor fuel excise not appear as a separate charge?
Motor fuel excise is levied per gallon at the distributor or terminal, not at retail, so it is embedded in the pump price and not separately stated. Because it is volumetric rather than ad valorem, liability per gallon is invariant to the retail price and its real value erodes with inflation absent legislative change.
Where does this state sit in the national distribution?
This state ranks 16 of 51, placing it in the upper third. Wide interstate dispersion in per-unit excise creates measurable cross-border purchasing effects, which several revenue departments model explicitly when forecasting receipts.
How does the diesel rate relate to the gasoline rate here?
Diesel is taxed at a rate set independently of gasoline and is lower in this state. The differential is generally justified by road-wear attribution to heavy vehicles rather than by fuel characteristics, and several states index the two grades differently.