The diesel vehicle drivers benefit since September 1 from a tax reduction of 20 cents per liter of diesel. The measure doubles the discount of 10 cents applied in August and will be in effect, in principle, until the next September 30.
The savings associated with the reduction reach 8 euros for a refueling of 40 liters, 10 euros for one of 50 liters, and 12 euros if a 60-liter tank is filled. However, this does not mean that all gas stations have to automatically reduce their prices by exactly 20 cents, because the measure is articulated through a reduction of the Hydrocarbons Tax and not as a direct discount that must appear separately on the receipt.
The change is provided for in the Royal Decree-Law 18/2026, of June 29, which incorporated a mechanism to adapt the taxation of fuels to their evolution. The maximum reduction has been activated after the price of diesel recorded in July an annual increase greater than the 15% established by the Government.
How much is saved per tank with the diesel discount
The following table reflects the theoretical tax savings derived from applying a reduction of 20 cents per liter. It also shows the improvement compared to August, when the discount was 10 cents.
| Liters refueled | Tax savings in September | Additional savings compared to August |
|---|---|---|
| 20 liters | 4 euros | 2 euros |
| 30 liters | 6 euros | 3 euros |
| 40 liters | 8 euros | 4 euros |
| 50 liters | 10 euros | 5 euros |
| 60 liters | 12 euros | 6 euros |
| 70 liters | 14 euros | 7 euros |
To calculate the savings of any refueling, it is enough to multiply the number of liters by 0.20 euros. A driver who refuels 35 liters benefits, for example, from a tax reduction equivalent to 7 euros.
Compared to August, the additional savings are obtained by multiplying the liters by 0.10 euros, since the discount has increased from 10 to 20 cents.
The discount benefits all diesel vehicle drivers
The reduction of the Hydrocarbons Tax applies to general use diesel, so it benefits both individuals and self-employed and companies. It is not necessary to submit an application, register, or use a specific card to benefit from this general reduction.
It is also not the 20-cent bonus that was in effect in 2022 and that appeared expressly itemized on the gas station receipt. On this occasion, the Government has reduced the rates of the Hydrocarbons Tax applicable during September.
The tax burden of general use diesel goes from 329 euros for every 1,000 liters expected without activating the extraordinary clause to 179 euros for every 1,000 liters. The joint reduction of the general and special rates thus reaches 150 euros for every 1,000 liters compared to the level initially set for September and 200 euros against the ordinary taxation taken as a reference by the decree.
This last difference is what the Government presents as a drop of 20 cents per liter.
Why diesel does not have to drop exactly 20 cents at all gas stations
The tax cut does not require service stations to show a fixed discount of 20 cents on the announced price nor guarantees that the liter of diesel will immediately drop by that amount.
The final price of fuels also depends on other components:
- The international price of oil.
- The price of diesel in wholesale markets.
- The exchange rate between the euro and the dollar.
- The costs of transportation and distribution.
- The margins applied by oil companies and service stations.
- The moment when each gas station renews its stock.
Stations that began September selling fuel purchased previously with a higher taxation may take longer to fully reflect the reduction. Additionally, a simultaneous increase in wholesale costs may absorb part of the tax relief.
For this reason, the 20 cents represent the tax savings established by the Government, but not necessarily an identical and immediate drop in the price that appears at the pump.
What happens with gasoline in September
The evolution is different for gasoline vehicles. Its tax reduction decreases from 10 cents per liter in August to 5 cents during September.
The reason is that the price of gasoline did not exceed in July the year-on-year threshold of 15% expected to activate the extraordinary clause. Diesel did exceed that limit, with a year-on-year increase of 15.7%, so it accesses the maximum discount.
This means that, keeping the rest of the factors constant, filling a gasoline tank is fiscally more expensive than in August.
| Fuel | Reduction in August | Reduction in September | Change for a 50-liter tank |
|---|---|---|---|
| Diesel | 10 cents per liter | 20 cents per liter | 5 euros more in savings |
| Gasoline | 10 cents per liter | 5 cents per liter | 2.50 euros less in savings |
Additional aid for professional transport
Professional carriers have a specific aid system different from the general tax reduction. The decree initially established a aid of 20 cents per liter for September. However, the regulation itself reduces that amount to 5 cents when the maximum reduction of the Hydrocarbon Tax is activated, as has happened this month. In this way, the general tax reduction is combined with specific support for professional transport.
To receive this additional aid, holders of vehicles entitled to professional diesel must pay for the fuel using the cards enabled for this system. The use of these cards is considered a request, and the Tax Agency calculates the amount at the end of each month to pay it via transfer.
There are also specific mechanisms for certain carriers who cannot access the professional diesel system, as well as differentiated aid for farmers, ranchers, and fishing companies.
Until when will the discount be in effect
The reduced rates of the Hydrocarbon Tax will be in effect from September 1 to September 30, 2026.
The current legislation does not contemplate its automatic continuity starting in October. To maintain the reduction, the Government would have to approve a new extension or modify the tax rates again before the end of the month. Therefore, unless a new measure is adopted, the extraordinary reduction of 20 cents per liter of diesel will cease to apply on October 1.