Which is More Expensive, Diesel or Petrol

From a pump-price perspective, diesel costs more per litre than petrol. However, diesel’s superior fuel economy means fewer fill-ups for long-distance drivers. For example, a Ford Focus 1.5 TDCi averages 60+ mpg, while the petrol variant manages around 45 mpg. If you cover 15,000+ miles annually, diesel’s efficiency could outweigh its higher price.

Diesel is generally more expensive per litre than petrol in the UK, but the total cost of ownership depends on several factors. As of recent data, diesel prices average around 5-10p higher per litre than petrol. However, diesel engines are typically 20-30% more fuel-efficient, meaning you may spend less on fuel over long distances.

Key considerations:

1. Fuel efficiency: Diesel cars, like the Volkswagen Golf TDI or BMW 320d, consume less fuel per mile, offsetting higher pump prices for high-mileage drivers.
2. Road tax: Diesel vehicles often face higher VED (Vehicle Excise Duty) rates, especially if they don’t meet RDE2 emissions standards.
3. Depreciation: Diesel cars may lose value faster due to shifting demand towards hybrids and EVs.
4. Urban driving: Short trips or city driving favour petrol engines, as diesel particulate filters (DPFs) can clog without regular motorway use.

For low-mileage drivers or those prioritising urban use, petrol is cheaper overall. High-mileage motorway commuters may still save with diesel despite the higher per-litre cost.

Generally speaking, petrol is more expensive as it requires higher purity than diesel, naturally resulting in higher refining costs. While the prices are quite similar, diesel can take you significantly further than petrol for the same volume.

How petrol works:

It ignites the spark plug by combusting fuel within the cylinder, causing gas expansion that converts chemical energy into mechanical energy, thereby driving the reciprocating motion in the engine cylinders.