It depends on two bets: how much the property appreciates and how much invested money earns. In an example with a R$ 500,000 property, R$ 100,000 down, a 30-year SAC loan at 11.5% a year, 5% appreciation, fixed income at 10% gross and rent adjusted 4.5% a year, buying and renting tie after 20 years when the starting rent is about R$ 2,972. With R$ 2,500 rent, renting and investing finishes ahead; with R$ 3,500, buying pulls ahead from year 5. That is why the tool shows a break-even rent and a sensitivity table instead of a single number.