Wow, you have managed to gather quite a significant amount within the family. How do you handle the repayment? Monthly, as it suits you at the moment? We are also considering accepting support but would prefer not to "involve" anyone from the family. But within the family, the interest rate is obviously the best, 0% :-D I'm still relatively new to the topic. How do I calculate how the monthly installment changes with the remaining debt if the interest suddenly is 6%?