Rent vs. Buy: The Questions the Math Can't Answer

Any honest rent-vs-buy calculation is dominated by two numbers nobody actually knows in advance: how much your home will appreciate, and what return you'd earn investing the money you didn't put into a down payment. Small changes to either assumption can flip which option comes out ahead — that's not a flaw in the math, it's just what happens when you're modelling the future.

Because of that sensitivity, treat any rent-vs-buy calculator (including ours) as a way to stress-test your own assumptions rather than a verdict. If buying only wins under optimistic appreciation assumptions, that's useful information about how much you're relying on a rising market.

The factors that often decide it in practice aren't in the spreadsheet at all: how long you're actually likely to stay (moving costs and selling costs eat into ownership's advantage over shorter horizons), how much you value the stability and control of owning, and whether renting frees up cash flow you'd genuinely invest — or just spend.

A practical rule of thumb: the shorter your expected time horizon, the more renting tends to make financial sense, because the fixed transaction costs of buying and selling a home (roughly 5-8% combined) take longer to be offset by building equity.