Consumers do not always correctly estimate the actual electricity costs of their devices. An example of this is the smartphone: Because we use it a lot and at the end of the day it thirsts for new energy from the socket, it is reasonable to assume that it also consumes a lot of electricity. How low the actual costs are, however, may surprise many. This is how you calculate the electricity costs of your mobile phone.
Three kinds of information are needed to calculate the electricity costs of a smartphone: the current electricity price, the capacity of the battery and the efficiency of the charging process. The easiest way to determine the current electricity price is because it is capped at 40 cents per kilowatt hour (kWh) for most consumers by the energy price brake. Exception: Anyone who has already consumed more than 80 percent of the previous year’s value pays 60 cents/kWh.
The capacity of the battery is a bit more cumbersome, because in most cases this is given in milliampere hours (mAh). In order to calculate the electricity costs of a full charge, however, one needs watt hours N(Wh), after all this corresponds to the format in which the electricity bill is billed. To do this, multiply the mAh specification for the battery by 0.00385 – a fully charged battery with 3,000 mAh therefore supplies around 11.55 Wh of energy.
The third variable is also the largest variable. The so-called efficiency indicates how much energy is lost when charging the mobile phone, for example due to heat generation. The consumer portal “Ökotest” assumes an efficiency of 80 percent as the usual average, i.e. 20 percent of the energy that is taken from the socket during charging is lost. Conversely, this means that 1.25 times as much electricity has to be drawn from the socket in order to fill up the battery.
Putting this information together in a simple formula (electricity price multiplied by the battery capacity divided by 800) quickly shows how cheap it actually is to charge a mobile phone. Using the example of a current iPhone 14, which according to the manufacturer has a battery capacity of 12.68 Wh, the price per full charge is 0.63 cents. Even those who have already used a lot of electricity and have to shell out 60 cents per kilowatt hour still pay a reasonable amount of 0.95 cents for a full charge.
To ensure that the mobile phone runs for a long time, many consumers use the battery capacity as a guide and make their purchasing decisions based on that. Many decide on devices with 4,500 mAh or more. The Samsung Galaxy A33 also falls into this category, whose 5,000 mAh mean a battery capacity of 19.25 Wh. With electricity costs of 40 cents, this means a price of 0.96 cents per full charge, with 60 cents it is 1.44 cents.
If you extrapolate these figures for the year, even frequent users who charge their mobile phone almost every day rarely end up with amounts of more than five euros a year. For example, if you pay 40 cents/kWh for your electricity and charge your new Pixel 7 (battery capacity according to the manufacturer: 4,355 mAh) from 33 to 100 percent every day, you will end up with an annual fee of around two euros.
