What does the deductibility of an expense mean?

It indicates what portion of the expense reduces the base used to estimate your taxes. For expenses, you can mark whether it is deductible and choose a percentage between 0% and 100%. Nett offers shortcuts for 0, 25, 50, 75 and 100%, but you can also select any percentage in between.

A category may suggest a typical percentage, but you decide whether to apply it or keep the current value. In Portugal, this section may be presented as the portion of the expense that counts towards the relevant annual check.