Compare the true cost of a low-interest loan against investing the same money — does a cheap loan actually pay off?
Monthly payments are drawn from the investment. What remains after the final payment is your profit.
Instead of paying cash upfront, what if you invested that money and took the loan? This calculator simulates investing the full loan amount on day one, then subtracting each monthly payment from that balance as it compounds. Whatever remains when the loan is paid off is your net gain versus paying cash.
The outcome hinges on the rate spread — invest rate minus loan APR. A positive spread means your investment grows faster than interest accumulates and financing wins. A negative spread means the loan costs more than you earn and paying cash would have been cheaper.