● Free tool

What will this property really cost you?

Enter the amount, the term and the rate your bank quoted you. You get the monthly payment, the total interest, and what the rent leaves once the loan is paid.

years
%
Monthly payment 1 160 €
Total interest78 385 €
Total repaid278 385 €
Rent minus payment-160 €

Arithmetic only. It ignores notary fees, registration duty, insurance, works, vacancy and tax, all of which move the real number. Proporio is not a credit intermediary and gives no financial advice.

The market

What the Belgian banks were quoting

Indicative fixed rates over 25 years for a strong file. Your rate depends on your own file, and these move.

BankFixed, 25 yearsNote
Belfius3,22 %Lowest of the three quoted
BNP Paribas Fortis3,30 %
KBC3,30 %
Argenta, Keytrade, ING, CrelanRegularly cited among the lowest, no figure recorded on this date
Figures recorded in February 2026, from broker barometers. They are here to give you an order of magnitude, not to replace an offer. For the same profile the spread between banks reaches 0.3 to 0.5 point, which is exactly why it is worth asking several. Proporio is not a credit intermediary, has no partnership with any bank listed here, and receives nothing if you go to one of them.

A monthly payment is only half the question. What decides whether a rental property works is the gap between what the loan takes out each month and what the rent brings in, once the months without a tenant and the works you did not plan are counted. This tool does the first half honestly: enter the figures your bank actually gave you, and read the payment, the interest over the whole term and the monthly gap against the rent. It is deliberately free of rates and lender names, because a rate printed on a page is out of date within weeks and because comparing offers is your bank advisor’s job, not a website’s. Inside Proporio, the same calculation runs on your real portfolio, next to the loans, the charges and the rents already recorded.

FAQ

Questions, answered

Which rate should I enter?
The one your bank quoted you, on the offer you have in hand. We publish none of our own: a rate printed on a page is out of date within weeks, and a wrong rate on a page that computes a payment is worse than no page.
Do you compare bank offers?
No. Advising on or arranging mortgage credit is a regulated activity in Belgium, and we are not registered for it. This page does arithmetic on figures you already have.
Is the calculation exact?
The formula is the standard fixed-rate annuity, so the payment is exact for a fixed-rate loan. What it does not include is everything around the loan: notary fees, registration duty, insurance, works, vacancy and tax.
What if the rent does not cover the payment?
That is common in the first years and not automatically a bad deal, since part of the payment builds equity. The figure to watch is how long the gap lasts and whether you can carry it through a vacant month.

Run the numbers on your real portfolio

Inside Proporio the same calculation sits next to your loans, charges and rents, and updates itself as they change.

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