How We Calculate: Rent vs. Buy

What This Calculator Does

The rent vs. buy calculator runs a year-by-year simulation of two parallel financial paths over a chosen time horizon. On the “buy” path, you purchase a home with a mortgage and pay all associated costs. On the “rent” path, you invest your down payment and the monthly cost difference (if renting is cheaper) in the stock market or other investments.

At the end of the time horizon, the calculator compares your total net position in each scenario: for buying, that’s the home equity (appreciated home value minus remaining mortgage) minus all costs paid. For renting, that’s the investment portfolio value minus all rent and insurance paid.

How the Simulation Works

Each year, the simulation tracks:

Buy path: Monthly mortgage payment (principal + interest split), property tax, insurance, HOA, and maintenance. The mortgage interest portion generates a simplified tax deduction. Home equity grows as the mortgage is paid down and the home appreciates.

Rent path: Monthly rent (increasing annually), renters insurance. The renter invests the down payment upfront and earns the specified investment return, compounding monthly.

The crossover point — where buying becomes cheaper than renting — is visible on the chart as the year where the buy cost line drops below the rent cost line.

How Each Variable Affects the Result

Time Horizon: The single most influential factor. Buying almost always loses over 1-3 years because of the transaction costs and the slow equity buildup. Over 7-10+ years, buying typically wins because home appreciation and principal paydown accumulate while rent keeps rising.

Home Appreciation vs. Investment Return: If the stock market returns 10% and homes appreciate 3%, the renter’s investment advantage grows over time. If home appreciation is 5% and investments return 6%, buying becomes more competitive. These two rates are the core tension in the comparison.

Rent Increase Rate: If rent rises faster than inflation (common in growing cities), renting becomes progressively more expensive. A 5% annual rent increase instead of 3% can shift the breakeven point by several years.

Down Payment: A larger down payment means more money taken out of investments (opportunity cost for the renter) but also a smaller mortgage with less interest. The net effect depends on the relationship between the mortgage rate and the investment return rate.

Common Misconceptions

The biggest misconception is “rent is throwing money away.” Rent pays for housing — a service you need regardless. The real question is whether the non-equity costs of owning (interest, taxes, insurance, maintenance) are more or less than rent. In expensive markets, the non-equity costs of a mortgage often exceed comparable rent.

Another misconception: “my home is an investment.” For most people, a primary residence is a consumption asset, not an investment. You can’t sell your home without needing somewhere else to live. Historical real (inflation-adjusted) home appreciation averages about 1% annually in the US — far below stock market returns.

Why This Calculator Exists

“Should I rent or buy?” is one of the most consequential financial decisions people face, and the answer genuinely depends on local conditions, time horizon, and individual circumstances. This calculator replaces gut feelings with a side-by-side numerical comparison using your actual numbers.