Running cost tool
Fuel Cost Calculator South Africa
Estimate petrol or diesel costs using pump price, fuel consumption and distance.
Estimate your fuel cost
Enter the current fuel price, your vehicle’s fuel consumption and how far you drive.
How to calculate fuel cost
Fuel cost is based on three main inputs: fuel price per litre, vehicle fuel consumption and distance driven. A car that uses 7.5 litres per 100 km will use about 7.5 litres to travel 100 km, before adjusting for real-world conditions.
The simplest formula is: distance divided by 100, multiplied by litres per 100 km, multiplied by fuel price per litre.
Why this matters when buying a used car
Fuel cost can make two cars with similar purchase prices feel very different to own. A cheaper car with poor fuel economy may cost more each month than a slightly more expensive but more efficient car.
This is especially important if you commute daily, drive long distances, use the car for work or compare petrol and diesel vehicles.
Why the calculator asks for the fuel price
Fuel prices change, so a fixed number would quickly become outdated. For the best estimate, enter the current pump price you expect to pay.
South Africa’s Department of Mineral and Petroleum Resources publishes official fuel price updates. You can use the official fuel price page as a starting point, then adjust for the price at your local station.
Why real-world fuel use can be higher
- Stop-start traffic can increase fuel use.
- Heavy acceleration and high speeds usually use more fuel.
- Under-inflated tyres can worsen economy.
- Roof boxes, heavy loads and towing can increase consumption.
- Air conditioning can affect consumption, especially in city driving.
- Older cars or poorly maintained cars may use more fuel than expected.
Related tools and guides
Use the Total Cost of Ownership Calculator to estimate fuel alongside finance, insurance, maintenance, tyres and other ownership costs. You can also use the Car Finance Calculator to estimate monthly vehicle repayments. If you are buying used, start with the Used Car Buying Guide.
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Frequently asked questions
How do I estimate monthly fuel cost?
Estimate your weekly kilometres, multiply by 52 and divide by 12 to get average monthly distance. Then apply your fuel consumption and fuel price.
What does litres per 100 km mean?
Litres per 100 km is the amount of fuel a car uses to travel 100 km. A lower number usually means better fuel economy.
Is diesel always cheaper to run?
Not always. Diesel cars may use less fuel, but diesel price, servicing costs, purchase price, mileage and the type of driving all matter.
Is this calculator exact?
No. It gives a planning estimate only. Real-world fuel use can vary significantly depending on the car, route and driver.
This calculator is for general information only. It is not financial, mechanical or motoring advice. Always check current fuel prices, vehicle condition and actual running costs before buying a car.