Including the costs of my home

Of course! Think, for example, of your electricity, heating, fire insurance and property tax. Naturally, these are costs that are linked in part to your self-employed activity as a secondary occupation, but also to a (large) extent to your private life.

For such costs, it is best to simply look at the square metres that your profession occupies in relation to the total habitable square metres of your home. Do you have an office space of 15 m² that you use almost exclusively for your secondary occupation? Do you also store some of your inventory in the garage, guest room or other room? Feel free to add these square metres to the 15 m² from your office space.Add up all these professionally used square metres and compare the total with the total surface area of your home. This will give you a percentage that you can use as the professional use percentage of your general housing costs.I have added a few extra square metres, as I am answering emails everywhere on my laptop (in the kitchen, living room, bedroom, etc.). The tax authorities are welcome to sit next to me for a day to check this