How do I calculate the capital gain or loss?

A profit or loss from a sale is, according to § 23 Income Tax Act, the difference between the sale price on the one hand and the acquisition or production costs and advertising costs on the other.

Acquisition costs include the pure purchase price and ancillary acquisition costs. The acquisition or production costs are reduced by depreciation for wear and tear (AfA), increased depreciation and special depreciation, insofar as they have been deducted in determining income. Ultimately, the deducted AfA is reversed.

Ancillary costs include, for example, consultancy fees, purchase fees, telephone charges or travel expenses, but they must all have been incurred in connection with the acquisition. Advertising costs must be apportioned if they are also related to other income.