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 litres. Multiply litres by 100, then divide by your car’s consumption figure in litres per 100 kilometres.
For example, at an assumed 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.
Use your own fuel consumption
Your car's brochure may list a fuel consumption value measured under controlled conditions. Short trips, traffic, air conditioning, hills, tyre pressure, luggage and driving style affect fuel consumption. Even the same driver may use a noticeably different amount in a city week and on a quiet highway trip.
To estimate your consumption, start with a full tank and record the distance until your next full refill. Note the litres added at that refill. Multiply those litres by 100 and divide by kilometres travelled. Repeat over several refills to find an average for your usual driving.
Allow for extra fuel and other travel costs
Petrol is only part of the cost of driving. Tyres, servicing, parking, tolls, insurance and depreciation also affect the cost of a car or commute. For a trip, allow extra fuel for traffic, detours and the distance to your next fuel stop.
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 allow for different driving conditions, 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 so they do not distort the fuel estimate.