Fuel tax has been reorganized in Portugal: New ISP amounts will be applied as of October 12

The Portuguese Government has determined the new week's amounts of the fuel tax ISP applied to gasoline and diesel. Portaria n.º 451-A/2026/1, published in Diário da República on 9 October, will come into force on Monday, 12 October.

On the same day, the Parliament also accepted the government initiative to continue the extraordinary tax reduction mechanism applied against the rise in fuel prices.

However, the announced discount amounts do not mean a new discount that will be automatically added to pump prices on October 12.

How much are the new ISP costs?

According to the official regulation, the ISP amounts to be applied on the Portuguese mainland were determined as follows:

fuel

ISP for 1,000 liters

Equivalent per liter

unleaded gasoline

€419.48

41,948 cents

diesel

€265.13

26,513 cents

These amounts include road service shares defined in the legislation.

There is a road service share of 87 euros per 1,000 liters for gasoline and 111 euros for diesel.

How many cents is the temporary tax deduction?

According to the government's statement, the provision of the temporary and extraordinary ISP discount mechanism in the new week is:

Approximately 9.65 cents per liter for diesel

Approximately 7.80 cents per liter on gasoline

These amounts represent the advantage applied to the reference tax levels within the scope of the temporary mechanism.

Therefore, it should not be concluded that these amounts will be deducted once again from the current pump price.

Why is the discount mechanism applied?

Government, It draws attention to the pressure that geopolitical and military developments in the Middle East put on the prices of oil and petroleum products.

The temporary ISP reduction aims to return the additional VAT revenue resulting from the increase in fuel prices compared to the determined reference period to the consumer through a tax reduction.

In the official regulation, the week of March 2-6 is used as a reference.

It was stated that the necessary condition for the week starting on October 12 was met for both diesel and gasoline.

Will pump prices change by the same amount?

No.

The sales price of fuel does not depend only on the ISP tax. International product prices, exchange rates, distribution expenses, company pricing and other taxes are also effective.

Therefore, even if the tax reduction continues, the pump price of a particular fuel may increase.

Likewise, if the price of petroleum products decreases, the final amount paid by the consumer may decrease.

What does Parliament's decision mean?

On October 9, the parliament passed the government's legislative initiative to continue the emergency ISP reduction mechanism.

Portaria n.º 451-A/2026/1 different legal proceedings published on the same day with this decision.

Portaria determines the concrete tax rates to be applied from 12 October.

The parliament's decision concerns the legal framework for the continuation of the discount mechanism.

Another must for pumps on October 17 will start

There is a separate regulation for fuel stations.

Within the scope of the previously published Decreto-Lei n.º 199/2026, stations must present tax deduction information showing the impact of ISP and VAT applied to fuels in a way visible to customers.

The start date of this notification obligation is 17 October.

Therefore, the ISP rate change on October 12 should not be confused with the pump notification obligation on October 17.

What should those driving in Portugal check?

As of October 12, the decisive factor for drivers who will purchase gasoline and diesel will be the liter price actually applied at the station.

The tax deduction amount and the final sales price are different indicators.

Moreover, it should not be assumed that the ISP rates set for mainland Portugal are automatically the same as the regional tax arrangements in the Azores and Madeira.

Resources

Diário da República — Portaria n.º 451-A/2026/1, 9 October 2026

https://diariodarepublica.pt/dr/detalhe/portaria/451-a-2026-1179331456

ECO — Governo autorizado a manter desconto sobre os combustíveis via ISP, 9 October 2026

https://eco.sapo.pt/2026/10/09/governo-autorizado-a-manter-desconto-sobre-os-combustiveis-via-isp/