1. What applies until 30 September
The rebate comes from the anti-crisis decree of June 2026, which cut the hydrocarbon tax by 20 cents a litre on diesel and 5 cents on petrol with an automatic trigger: the 20 cents for diesel apply once its annual inflation exceeds 15 per cent, which happened in July at 15.7 per cent; petrol at 7.3 per cent stayed below (El Español, 1 September 2026). Hence 10 cents on both fuels in August and, from 1 September, 20 cents on diesel and 5 on petrol. Royal Decree-Law 18/2026 governs the aid and sets its expiry at 30 September (El Español).
With that rebate, diesel A cost €1.829 and petrol 95 €1.867 on 22 September, about five cents more than ten days earlier (Motor16). Diesel only looks cheaper than petrol in Spain because the rebate is asymmetric; without it diesel would sit 11 cents higher, for the reasons on Why is diesel more expensive than petrol.
2. What happens on 1 October if nothing is extended
If the rebate lapses on 30 September, the hydrocarbon tax on diesel rises by 20 cents a litre and 21 per cent VAT is charged on top: 24.2 cents more at the pump without the market moving at all (Motor16, 22 September). On the €1.829 of 22 September, diesel A would land around €2.07; Motor16 says €2.1 to €2.2 because it expects the market to keep rising. Petrol 95 would rise by 5 cents plus VAT, about 6 cents, to roughly €1.93.
| Fuel | 22 September | Rebate | 1 October without extension (arithmetic) |
|---|---|---|---|
| Diesel A | €1.829/L | 20 ct + VAT = 24.2 ct | ≈ €2.07/L |
| Petrol 95 | €1.867/L | 5 ct + VAT = 6.05 ct | ≈ €1.93/L |
That is a sum on Motor16's prices of 22 September; the actual price on 1 October also depends on crude and gasoil on the world market, where Brent stood at $99.97 on 22 September (our API) and gasoil rose while crude fell (see Diesel shortage winter 2026/27). A 50-litre tank of diesel would cost €12.10 more overnight.
3. What the government is preparing, and what is not decided
The government plans to approve a new fuel decree at the cabinet meeting of the last week of September, aimed at families, professional transport and agriculture; on 18 September "none of the measures is approved yet" (Qué!). On the table are an extension of the rebates expiring at month-end, a one-off €300 payment for low incomes proposed by the CCOO union that would reach about 10 million people, and a return of the Iberian cap on gas prices. Officials only say they are "monitoring the situation closely" without confirming an extension (Motor16, 22 September).
The backdrop is inflation: 4.3 per cent in August, seven tenths above July, with petrol and diesel about 30 per cent dearer than in June (Qué!). Germany decided on 19 September to cut about 17 cents off both fuels from October to December (see Germany's fuel tax cut); France chose on 22 September to pay €100 to 5.5 million heavy commuters rather than lower the price. Spain decides in the coming days; until the official gazette publishes the decree, the date that counts is 30 September.
4. What drivers, visitors and fleets should do before 1 October
If you drive diesel in Spain, fill up on 30 September: if the government extends, you lose nothing; if it does not, you save €12 per 50 litres. For petrol the difference is €3 a tank, not worth a queue. Visitors driving into Spain in October should stop counting on the rebate and compare with France (gazole €2.41 on 20 September, Hérault Tribune) and Germany (€2.471 on 17 September, ADAC): even without the rebate, Spanish diesel at around €2.07 would remain the cheapest of the three. Fleets should check whether their fuel card applies the rebate at the pump or refunds it later, because the month-end changeover can be handled differently.
For heating oil the rebate changes nothing: the reports cited concern road fuels, and gasóleo C stood at 168.7 cents a litre on 17 September (calienteybarato.com), driven by the same distillate market as diesel. Spain's own ordering rule for heating oil is on our Spanish page Gasóleo de calefacción: ¿comprar ahora o esperar?; the US version of the rule is on Heating oil: buy now or wait?.
See in a minute what 24 cents more per litre does to your annual budget.
Calculate my fuel costs