How to calculate the rental yield?

Negotiated sale price: 150,000 €
Monthly rent: 1,000 € / month
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Income per year: 1,000 € x 12 / year = 12,000 € / year
How to estimate income per year: Estimated price per m2 x Area in m2 = Rent per month
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Income per year including tax: € 12,000 – € 500 Charges – € 3,000 credit = € 6,500 / year including tax
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Calculate the yield :
(Rental income per year / Sale price negotiated) x 100 = Yield%
Result: (6,500 / 150,000) x 100 = 4.33%