The basic principles that the deductible expenses must comply with in the IRPF and for an economic activity.
In the calculation of the net income of the economic activities whose system of determination is the direct estimate, there is a generic reference to the rules of Corporation Tax, which leads us to the determination of the taxable base by correcting, through the application of the provisions established by the Law of Corporations, the accounting result determined in accordance with the rules set forth in the Commercial Code.
According to this reference, the deductibility of expenses is conditioned by the principle of correlation with income, and it must therefore be demonstrated that they have been incurred in the course of the activity and that they are necessary to obtain the income. So when there is no such linkage to the activity or need for it, they could not be considered deductible.
The deductibility of expenses is also conditioned by the fact that they are duly justified by the original invoice or equivalent document temporarily imputed to the corresponding fiscal year and that they are accounted for or recorded in the obligatory registry books that taxpayers who carry out economic activities must keep, provided that they determine their net yield in direct estimation in any of its modalities.
Article 28.1 Law 35 / 2006 , of 28 November 2006 , on Personal Income Tax
Article 10.3 Law 27 / 2014 , of 27 November 2014, on Corporation Tax
D.G.T. Binding Consultation V 0949 - 15 , of 26 March 2015
D.G.T. Binding Consultation V 1173 - 15 , of 16 April 2015
D.G.T. Binding Consultation V 1853 - 15 , of 12 June 2015
D.G.T. Binding Consultation V 1724 - 15 , of 02 June 2015
Royal Decree 1619/2012 of 30 November 2012 approving the Regulation governing invoicing obligations