There is no single "cheapest" fuel — it depends on how much you drive and where. Here is how the four options stack up in 2026, and how to work out the right one for you.
Petrol
Lowest upfront price and available everywhere, but the highest running cost per km. Best for low-usage city drivers who value the cheapest sticker price and don’t rack up big monthly distances.
Diesel
Costs more upfront and diesel is cheaper than petrol per litre with better mileage — but the savings only pay back at high annual distances. Best for highway-heavy drivers and larger vehicles.
CNG
The clear winner on running cost for many buyers, which is why CNG and hybrids recently overtook petrol in new-car sales. Trade-offs: a smaller boot (cylinder), a modest price premium, and you need CNG pumps on your routes. Best for high-usage city drivers with CNG availability.
Electric (EV)
Lowest running cost of all if you can charge at home, plus low maintenance. Trade-offs: highest upfront price and you must plan charging on long trips. Best for predictable daily drivers with home charging; increasingly viable as charging networks expand.
How to decide — run your own numbers
The honest answer comes from your own usage. Estimate your monthly and yearly spend with our fuel cost calculator, compare it across fuel types, and for a real trip use the trip cost calculator — it shows the petrol/diesel cost and an EV charging estimate side by side, so you can see the gap for your actual routes.
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