Renting against buying.

What the calculator assumes

• —Owning is valued as what you'd walk away with if you sold that month: the appreciated price, minus what's left on the loan, minus selling costs.
• —The renter invests the cash buying would have consumed — the down payment and closing costs on day one — plus the monthly difference in every month renting is cheaper. The owner does the same in months when owning is cheaper. Skipping either of those rigs the answer.
• —Mortgage insurance is charged monthly whenever the down payment is under 20%, priced off the original loan, and stops once the balance falls to 80% of the purchase price.
• —Home appreciation, rent growth, and investment returns all compound monthly at the annual rates you set.
• —Property tax and maintenance are charged against the home's current value, so they rise with it.

What it leaves out

• —Tax treatment is not modeled. Mortgage-interest and property-tax deductions and the primary-home capital-gains exclusion can favor a qualifying owner; tax on the renter's investment growth can also reduce the renting result shown here. Leaving both out can make renting look better, though the real effect depends on eligibility and account type.
• —Loan points, origination fees, and mortgage insurance paid as a single up-front premium are not included; only the monthly premium is.
• —Insurance, HOA dues, and renter's insurance are held flat in today's dollars. In reality they rise, and homeowner's premiums have lately risen faster than general inflation.
• —Property tax is assumed to track the home's value. Many states cap reassessment or reset it only on sale, which can make owning materially cheaper than this shows.
• —Maintenance is a smooth annual percentage, not the lumpy reality of a roof.
• —Nothing here prices the parts that usually decide it: how long you'll actually stay, whether you'd have to move for work, and what a down payment does to the rest of your plan.