When planning a drive, the first number you often know is what you can spend. From that budget we can estimate how much fuel you can buy and how many kilometres it may cover.
The simple calculation
Divide your money by the local price per litre to get fuel volume. Multiply litres by 100, then divide by your car’s consumption figure in litres per 100 kilometres.
For instance, using illustrative assumptions of R22 per litre and 7 litres per 100 km, a R500 budget buys about 22.7 litres and could cover around 325 km.
What changes real-world range?
Fuel consumption changes with city traffic, hills, weather, load and driving style. Use your own trip-computer average rather than the published lab value where possible.
Enter your amount in the petrol calculator and edit the price for your area.
Measure your own driving rather than trusting one test-cycle figure
Your car's brochure may list a fuel consumption value measured under controlled conditions. In the real world, short trips in traffic, air-conditioning, gradients, tyre inflation, luggage and driving style affect litres per 100 km. Even the same driver may use a noticeably different amount in a city week and on a quiet highway trip.
A practical way to estimate your consumption is to record distance between two fill-ups and litres added during the second fill. Multiply litres used by 100 and divide by kilometres travelled. Repeat across several similar journeys to find a range rather than one supposedly precise number.
Keep reserve and running costs separate
When comparing cars or commuting options, petrol is only the fuel portion. Tyres, servicing, parking, tolls, insurance and depreciation can matter as much or more over time. And when planning a trip, never spend the mathematical final litre of your estimate: a fuel stop or congestion may change the journey.
The petrol price used by our calculator is editable because pump prices differ by location, fuel grade and date. The calculator does not pull live fuel prices. For a decision today, enter the displayed pump price or verified recent retailer price.
Plan the return trip, not just the outbound drive
A trip computer's range estimate is not a promise. Suppose a round trip is 320 km and the car has averaged 8 L/100 km: the arithmetic suggests 25.6 litres. At a hypothetical R25/litre, that is R640 before any reserve. If you only budget R500, reduce the distance or make a different transport plan instead of assuming the car will achieve a lower consumption rate.
To stress-test a journey, run the fuel calculator twice: once with your normal consumption and again with a higher value representing traffic or a fully loaded car. Record tolls and parking separately rather than hiding them inside the petrol price.