Understanding Fuel Consumption — Petrol, Diesel, Hybrid & Electric

Fuel is one of the largest ongoing costs of owning a car, and the figure quoted in the brochure — litres per 100km — directly shapes your monthly budget. A car using 5 L/100km versus 9 L/100km can mean hundreds of rands a month difference for the same trips.

Petrol vs diesel

Petrol engines are cheaper to buy, smoother and the obvious choice for lower-mileage city driving. Diesels cost more upfront but use less fuel and produce huge low-down torque — ideal for high-mileage drivers, long-distance commuters, towing and bakkies. The rule of thumb: the more kilometres you do, the more a diesel pays for itself.

Hybrid and electric

Hybrids pair a petrol engine with an electric motor to slash fuel use, especially in traffic, with no charging required — Toyota's self-charging hybrids are the proven example. Fully electric cars eliminate fuel bills entirely and cost a fraction to 'refuel' at home, with far lower servicing costs; the trade-offs are range and charging planning. South Africa's EV and hybrid range is growing fast.

Why your real figure differs from the brochure

The consumption figure on a spec sheet is measured under controlled test conditions, and your real-world number will almost always be a little higher. That's not dishonesty — it's the gap between a laboratory cycle and the messy reality of traffic, hills, air-conditioning, a loaded boot and your right foot.

The good news is that the brochure figure is still a fair way to compare cars against each other, because they're all measured the same way. And you have real influence over your own number: gentle acceleration, maintaining momentum rather than braking and surging, correct tyre pressures, and not carrying unnecessary weight can all shave litres off your monthly bill. A smooth driver in a thirsty car can easily beat an aggressive one in an economical car.