Living area less than specified

Living area less than stated

Hello,

I measured my apartment today and found that my living area is about 12% smaller than stated in the rental agreement.
Can I now reclaim my rent?

Yes, if you have measured everything correctly, then you can reclaim the rent retroactively for 3 years and adjust the future payments.

I think I have the same problem but how do I calculate the living area, I don’t want to make any mistakes, I heard that there are probably regulations about what is only half counted and what is not counted at all etc.

I once saw a SternTV segment on this, it's not that difficult. But I don't want to say anything wrong, I would just google it.

You can also simply hire an expert to measure it. If you are in the right, you can charge your landlord for it. But if you are not in the right, you will be stuck with the costs.

How high are the costs?