Please do not calculate only the loan costs as an expense, but also the increased additional costs, for example compared to a smaller rental apartment. Someone already said that. Start building reserves early; with a house, there is no landlord who will replace broken windows, heating, whatever. Does the commute change? If yes: set higher fuel costs and wear and tear. Also please find out about [Kita fees]. For us, they are €600/month (!!!), which you should first have available. It does not have to be accurate to the cent, but with such a decision, it is negligent to build the household budget solely on the monthly expenses from loan payments.