What is profit (Gewinn)?

Profit (Gewinn) is how much money you make after expenses. Profit is not the same as revenue (Umsatz).

For example, you have a product that costs 6€ to make, and sells for 10€. Your revenue is 10€ per unit, and your profit is 4€ per unit.

You only pay income tax and trade tax on your profit, not your revenue.