Financing calculator with variables wanted

Hello everyone,
we are at the beginning of the idea to buy or build a house.
For us, the first priority is therefore the question of what we can afford and what we want to afford.
Since we do not have the normal financial situation, I am looking for a financing calculator online where I can make a few flexible settings. For example, in 3 years we will have rental income, but not currently, and in a few years we will receive money that we have invested securely. Is there such a financing calculator that can be fed with more information?
Thanks to you in advance.

It's just a question of what you want to use the computer for. As a guideline for you? To estimate what you can afford? Or to determine what a bank would give you? Because those are two completely different things, especially if you want to factor in future income. A bank will first of all consider the current status; everything else is uncertain future speculation. I would rather associate secure future cash inflows with the topic of maturities. For example, if you expect 150k in 10 years, (partial) maturities with shorter fixed interest periods might make sense for you. Currently, it is usually recommended to choose relatively long maturities (+/- 20 years).

for example, in 3 years we will have rental income, but not yet currently

The bank is not interested in that, nor in inheritances or the like. That is why the calculators on the internet are not designed for that.

we will receive money in a few years

Nevertheless, this amount has to be financed. Only in discussions with a bank or an advisor can special conditions be considered.

I have found that special arrangements are best agreed upon with the [Hausbank/Geschäftsbank]. With large institutions, you immediately fall through the cracks; they do not assess individually, they conduct mass business.

Thanks first of all for the quick response. Yes, in the first step it is about a rough calculation of what we can afford. However, I think that since the future rental income concerns the current apartment, the bank will certainly include this in the calculation. Which calculator can you recommend for me?

Yes, the first step is a rough calculation of what we can afford. However, I think since the future rental income comes from the current apartment, the bank will certainly include this in the calculation. Which calculator can you recommend for me?

You don't need a calculator for that. A sheet of paper is enough:

Net income he/she (contractual payments like Christmas bonus can be included or alternatively kept as a buffer for yourself)
Child benefit (applicable for young children)
Rental income minus 20% operating costs
minus living expenses (at least 40% of net income) / retirement provision / existing loans

What is left over you can spend. Calculate with a 3% minimum annuity and you have your maximum financing volume.