How petrol prices affect the real cost of owning a car in South Africa

A vehicle costs more than its purchase price

The price of a car is only the beginning of what it costs to own one. After purchase, a vehicle continues to generate expenses through fuel, finance, insurance, licensing, servicing, tyres, repairs, parking and depreciation.

For many South African motorists, petrol is one of the most visible and frequently changing costs. A fuel-price increase may appear small when expressed as a few cents or rand per litre, but its effect accumulates every time the vehicle is filled. Over a month or a year, that increase can materially change the real cost of keeping the vehicle on the road.

Why petrol prices change

South African fuel prices are influenced by more than one factor. International petroleum prices, the rand exchange rate, transport and distribution costs, regulated margins, and taxes or levies all contribute to the final pump price.

Because several of these factors can move independently, local petrol prices may rise even when only one part of the pricing chain changes. Fuel prices are also adjusted periodically, which means motorists may experience repeated changes during the ownership period.

The practical implication is that fuel should not be treated as a fixed monthly amount. It is a variable operating cost that can move up or down while the finance instalment remains unchanged.

The difference between purchase affordability and ownership affordability

A vehicle may appear affordable when the monthly finance instalment fits within a household budget. That calculation can be misleading if it excludes the cost of using the vehicle.

Ownership affordability should include the full monthly cost of operating and maintaining the car. For a petrol vehicle, this means estimating how much fuel the owner is likely to use under normal conditions, not relying only on the manufacturer's laboratory consumption figure.

Urban congestion, short trips, heavy loads, air-conditioning, aggressive acceleration, tyre pressure, road gradients and vehicle condition can all increase real-world fuel consumption.

How a petrol-price increase changes a monthly budget

The effect of a fuel-price increase depends on three numbers: the vehicle's real fuel consumption, the distance driven and the price paid per litre.

A driver who travels a short distance in an efficient vehicle may feel a moderate increase. A long-distance commuter, delivery driver or family using a larger vehicle may experience a much greater change.

This is why the same petrol-price announcement does not affect every owner equally. The monthly impact is determined by use, not merely by the size of the official increase.

Fuel cost can influence which vehicle is genuinely affordable

Two vehicles with similar purchase prices can have very different ownership costs. A larger engine, heavier body, older drivetrain or less efficient transmission may increase fuel use significantly over time.

When comparing vehicles, buyers should consider expected monthly distance, realistic fuel consumption, the type of driving involved, the fuel grade required, tank size, servicing and tyre costs, and likely resale demand.

The cheapest vehicle to buy is not always the cheapest vehicle to own.

Why commuting patterns matter

South African motorists often travel long distances between residential areas, workplaces, schools and transport hubs. A vehicle used for daily commuting can therefore consume far more fuel than one used mainly for occasional local trips.

Repeated stop-start traffic also affects consumption. A route that is shorter in kilometres may still use more fuel if it involves congestion, idling and frequent acceleration.

Owners should assess fuel cost using their actual route and weekly routine. A realistic estimate is more useful than a general national average.

Petrol prices and vehicle resale demand

Fuel prices can also influence the used-vehicle market. When operating costs rise, buyers may place greater value on smaller engines, efficient drivetrains and vehicles with lower running costs.

This does not mean that every fuel-efficient car will automatically hold its value better, or that larger vehicles will always lose demand. Resale value still depends on condition, mileage, service history, reliability, specification and market supply.

However, sustained high fuel costs can change what buyers consider practical. A vehicle that is expensive to run may appeal to a narrower group of future buyers.

Fuel prices also affect costs beyond the fuel tank

Petrol and diesel prices influence transport and logistics costs throughout the economy. Businesses may pay more to move goods, operate service vehicles or deliver parts. Those increases can eventually affect the prices of maintenance items, repairs, tyres and other household goods.

The effect on a vehicle owner is therefore not limited to the amount paid at the filling station. Fuel-price movements can contribute to broader cost pressure across the entire ownership environment.

How to estimate your real monthly fuel cost

A practical estimate can be built from recent driving data:

• Record the distance travelled between full tanks.
• Record the litres required to refill the tank.
• Divide litres used by kilometres travelled and multiply by 100 to calculate litres per 100 kilometres.
• Divide your expected monthly kilometres by 100, then multiply by your fuel-consumption figure in litres per 100 kilometres to estimate monthly litres used.
• Multiply the estimated litres by the current price per litre.

For example, 1,000 km at 8 L/100 km uses an estimated 1,000 × 8 ÷ 100 = 80 litres. Multiply 80 litres by your actual price per litre to estimate the fuel cost.

• Add a reasonable buffer for congestion, detours and price changes.

Using several refuelling cycles produces a more reliable estimate than using one tank.

Ways to reduce unnecessary fuel use

Owners cannot control the regulated pump price, but they can reduce avoidable consumption. Practical measures include:

• Maintaining correct tyre pressure
• Servicing the vehicle according to schedule
• Addressing warning lights and mechanical faults promptly
• Removing unnecessary weight
• Combining errands where practical
• Avoiding prolonged idling
• Accelerating and braking smoothly
• Planning routes around severe congestion
• Monitoring consumption for sudden changes

A sudden increase in fuel use may indicate tyre, engine, sensor or driving-condition problems that require investigation.

Why fuel economy should not be considered in isolation

A highly efficient vehicle is not automatically the best financial choice if it carries a much higher purchase price, costly finance agreement, expensive maintenance requirements or poor resale prospects.

Total ownership cost should balance fuel economy with purchase price, finance cost, insurance costs, maintenance, depreciation and the owner's actual needs.

The correct question is not simply, "Which car uses the least petrol?" It is, "Which vehicle delivers the most suitable overall cost for how I will use it?"

The practical conclusion

Petrol prices affect far more than the amount displayed on a fuel pump. They influence monthly household budgets, commuting choices, vehicle comparisons, operating behaviour and, over time, used-vehicle demand.

For South African motorists, the real cost of owning a car should therefore be calculated across the full ownership period. The purchase price and monthly instalment matter, but so do the kilometres travelled, real-world fuel consumption and the possibility of future fuel-price increases.

A vehicle is genuinely affordable only when the owner can reasonably carry both the cost of buying it and the cost of using it.