Gasoline prices have been on a rollercoaster ride for years. Anyone who travels a lot knows the dilemma: fill the entire tank straight away or would it be better to fill only part of it and go back to the pump later? There is a little science behind this seemingly banal question, and the answer is less clear-cut than you might think.
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At first glance, filling the tank completely seems logical. Anyone who has found a cheap gas station will benefit the most if the entire quantity is filled at that price. Partial refueling, on the other hand, compensates for price fluctuations because an average is obtained over many refueling stops. In everyday life, however, it turns out that the difference between the two strategies is smaller than expected.
Practical test
Stern magazine investigated exactly this question and conducted a self-experiment over several weeks. Two reporters drove identical vehicles, one always filling up the tank, the other always filling smaller amounts. In the end there was a winner. The reporter with many small fuel stops achieved a better average price, with a price fluctuation of 17 cents, than reporter two with half as many stops and filling up every time.
The decisive factor was less the filling strategy than the price development in the respective week. The conclusion of the test: The differences are real, but not big enough to derive a general rule from them.
The effect of small steps
Economic experts like to refer to the so-called cost averaging effect. Those who regularly invest small sums compensate for market fluctuations, according to the Volksbank. When applied to refueling, this means that anyone who only fills up a certain amount will move towards the average price in the long term. The Stuttgarter Zeitung notes that although this effect exists, it is hardly significant when it comes to fuel. Fuel prices do not fluctuate nearly as much as share prices, so the savings effect remains manageable. It is also difficult to estimate how often or when the tank needs to be refilled, which cannot be compared with the planned implementation of a savings plan on the capital markets.
Place and time are more important
The place and time of refueling have a greater impact. The ADAC has determined that prices at motorway filling stations can be up to 57 cents per liter higher than at stations a few kilometers away. The difference becomes even clearer when you look at the time of day. DA Direkt found that prices in the evening are significantly lower than in the morning. So if you plan consciously, you will save more money by choosing the gas station and time than by deciding between full and partial refueling.
Saving tips beyond the filling quantity
Finanztip advises using digital helpers. Price apps show in real time where the cheapest gas station is. Then there is the choice of time: a short stop in the evening can bring significantly more over the course of the year than the choice between full or partial refueling ever could. If you also pay attention to the technical basics – tire pressure, regular maintenance and a quiet driving style – you can reduce fuel costs even further.
Editorial team finanzen.net
