PTT and Bangchak increased diesel prices on September 24

The September 24 increase lifted B7 to THB 41.44

Bangchak's historical price data shows standard diesel at THB 40.69 and B20 at THB 35.69 on September 15. From September 24, both were THB 0.75 higher, at THB 41.44 and THB 36.44 per litre. PTT Station announced the same base diesel figures for Bangkok.

Petrol and the main gasohol grades were unchanged at the two networks on that adjustment. The published Bangkok figures were quoted before a local maintenance tax, so the amount displayed at an individual forecourt can vary by location.

Provincial Energy Office tables dated September 26 continued to list B7 at THB 41.44 and B20 at THB 36.44 across major brands. That confirms the September 24 increase remained reflected in the official data two days later, without implying that the same price must apply at every station on September 27 or beyond.

For practical context, see How to buy property in Thailand. This development also connects with Thailand Fuel Prices Rose Twice in One Week in August.

The practical impact depends on mileage and transport use

For a household, the effect is straightforward: diesel becomes a larger recurring expense, with the impact concentrated among people who drive longer distances or use their vehicle frequently. Businesses running delivery vehicles, service fleets or other diesel-dependent operations also face a higher fuel input cost.

The pump-price change is not a one-for-one forecast for delivery fees or retail prices. Fuel is only one component of those costs, and businesses differ in route length, contracts, vehicle efficiency and pricing decisions. A useful budget check is therefore based on actual fuel consumption and the price at the station normally used, rather than a single national headline figure.