Rental investing is arithmetic before it is real estate: does the rent cover the debt, what is the real return, and does this property beat an index fund. These tools answer all three honestly.
Monthly rent ≥ 1% of purchase price is the classic screen. At current prices and rates it fails in most metros — treat it as a quick filter, then run the real math: P&I plus ~40% of rent for taxes, insurance, maintenance, and vacancy against the rent.
Total return = cash flow + principal paydown + appreciation, divided by cash invested (down payment + closing + rehab). The ROI calculator annualizes it so you can compare against index funds honestly — many rentals lose that comparison once effort is priced in.
Compare guaranteed vs leveraged return: paying down earns the mortgage APR risk-free; the next property earns rental ROI amplified by leverage but with concentration risk. The loan payoff and ROI calculators quantify both paths with your numbers.