At the highest level of taxes (>38 080€), in Belgium 100€ would result in a net of:

- ~37€ if the self-employment is not subject to VAT (less than 25.000€ per year as self-employed)

- ~30.7€ if subject to VAT

(100€ / 1.21) [VAT] * (1 - 0.21) [Social contributions] * (1 - 0.53) [Federal tax 50% + local tax 50% * 6%]