Any driver who thinks of gasoline or diesel will surely twist his nose, and with good reason: the price of fuel is going out of control, reaching figures that are simply prohibitive. Diesel was supposed to be the cheap alternative now, is it still the worst? To what extent is it more interesting to buy a diesel car than a gasoline one?

Go ahead, here we are not going to deal with issues such as the demonization of diesel and the general persecution it suffers from all angles (most of the time in an unjustified way, since modern diesels are very clean), or possible maintenance costs, we are simply going to face the question from pure mathematics.

The question is simple: from what mileage is it more interesting to buy a diesel than a gasoline?

The quick answer is easy: if you are going to accumulate many kilometers, it is always better to opt for a diesel vehicle. Now, the complete answer involves taking into account quite a few factors and doing calculations:

- How much is the car worth in equivalent gasoline and diesel versions
- Average consumption of each of the two versions
- What is the price of each fuel (although in the long term there are obviously fluctuations)

With these elements and doing some more or less simple accounts, it is possible to find out how many kilometers it is necessary to travel with a car so that a diesel is more profitable, which initially implies a greater economic outlay (they are more expensive) but they are cheaper in use. (diesel costs less than gasoline).

As the market is really wide and the consumptions have nothing to do with each other, it is difficult to launch an average figure, but it is usually established as the optimal point to buy a diesel if you are going to do an annual mileage of between 20,000 and 25,000 kilometers.

In addition, it is as the car approaches 200,000 kilometers that the initial investment made in the vehicle is truly amortized.

## The formula to do the calculation

There is a theoretical formula that can be applied to calculate at a specific time how many kilometers will be necessary to make the diesel car profitable. Although as a drawback, it does not take into account variations in the price of crude oil.

On the one hand, you have to take the price of the diesel car and subtract the price of the gasoline car. We keep the result for now.

Secondly, we multiply the consumption of gasoline by the price of gasoline and divide the figure by 100. Thirdly, we do the same operation with the consumption of diesel by the price of diesel and dividing again by 100. The next thing is to subtract the result of gasoline that of diesel.

The last step is to divide the first number (the price difference between the two cars) by the last and what it gives is the number of kilometers after which the diesel variant would be more interesting.

## An example that makes it clear

These things are best seen with examples and we have chosen to carry it out the new Opel Astra, since it is available with gasoline and diesel engines of identical power, 130 CV, and in the same finish, so it is an ideal scenario. .

The Opel with a diesel engine costs 25,300 euros and the one with a gasoline engine costs 24,630 euros. The difference between the two is 670 euros.

Now the gasoline operation: it has an average consumption of 5.5 liters and the price of gasoline today is 1.98 euros per liter. Multiplying both numbers and dividing them by 100, the result is 0.1045.

Diesel shift: it has an average consumption of 4.3 liters and the price of diesel is 1.89 euros per liter. Multiplying them and dividing by 100 the result is 0.08127.

Now we subtract both the second result from the first and we get 0.02323.

The last step is to divide the difference between the price of the two cars, which was 670 euros, between this last figure, which indicates that it is necessary to travel 28,842 kilometers for the diesel Opel Astra to be more interesting than gasoline.