Building savings contract pays more interest than construction financing charges interest

If I have a building savings contract where I receive 3% interest and at the same time pay for a construction loan with 2% interest – does it then make sense to cancel the building savings contract and put the amount as a special repayment into the loan?

My thoughts: I am not sure if I am answering this question too simply for myself with a "No, keep the building savings contract running and use it as a special repayment after maturity." The interest on my construction loan (annuity loan) is fixed until the end of the term, which is in about 25 years. If I repay now on the construction loan, I effectively benefit for 25 years, since from the day of the special repayment my repayment amount increases directly.

I am not very skilled in financial matters, it would be great if someone could help me.

As long as the building savings contract is still running and accruing interest, you generate 1% more interest than the cost of your contract. So let it run until the end of the savings phase, or as long as you receive the 3% interest, and only then empty it and use it as a special repayment. Any applicable account management fees can dilute the result. You need to calculate this with your specific numbers and data.

Always pay attention to the capital tax. You don't want to have to remit it at some point.

As HilfeHilfe already said, you may have to pay capital gains tax on the home savings contract once the saver allowance is exceeded. That would be 26.375% tax on the earnings above that amount.

You already mentioned the higher repayment portion of the installment due to special repayments. This effect should not be underestimated and ensures that you are debt-free before the end of the 25 years (assumption: full repayment) and possibly save several months/years of installments (including interest).

It is best if you calculate both scenarios in an Excel spreadsheet based on your circumstances over the entire term and then compare.

I did this for my situation as well: I have an annuity loan with 1.24% interest over 20 years. Now the question arises at what percentage of interest a daily or fixed deposit account performs better than annual special repayments. In my example, this was only the case from an interest rate of 3.6%, due to the above-mentioned points, so significantly higher than the 1.24% of the loan!

pay a mortgage with 2% interest

Where do you get financing with 2% interest? Or have you had the contract for a long time?

In my example, this was only the case from an interest rate of 3.6% due to the points mentioned above, so significantly more than the 1.24% of the loan!

That cannot be. You have the compound interest effect on both sides. In the loan in the form of saved interest and higher repayment. In the investment in the form of compound interest. Therefore, it is sufficient if you compare the loan interest rate with the net investment return after taxes. For simplicity, I assume that you pay 25% capital gains tax on it; in practice, this can be less due to allowances or slightly more due to church tax. For the rough calculation, however, this is enough, so in your case we have 1.24%/0.75 = 1.65%.