Rent vs Buy Calculator

Compare the total cost of buying a home versus renting over a chosen period.

Inputs

The formula

r = Mortgage rate / 100 / 12 n = Term x 12 k = Years x 12
Loan L = Price - Down payment
Payment M = L x r / (1 - (1 + r)^-n)
Owning per month = M + Price x Tax% / 100 / 12 + Insurance / 12 + HOA
Cash paid out = Down payment + Owning per month x k
Balance B = L(1 + r)^k - M((1 + r)^k - 1) / r
Home value = Price x (1 + Appreciation)^Years
Net cost of buying = Cash paid out - (Home value - B)
Rent paid = 12 x Rent each year, Rent x (1 + Increase) the next
Investment growth = Down payment x ((1 + Return)^Years - 1)
Net cost of renting = Rent paid - Investment growth
Down payment
Price multiplied by the percentage you enter. It is subtracted from the price to get the loan, and it is also the sum the renting side invests instead of spending.
Home appreciation per year
The rate the home value is grown at, compounded once a year for the full comparison period. The tool defaults to 3, and that default is an assumption you can change, not a forecast of any market.
Investment return on the down payment if renting
The rate the unspent down payment is grown at, compounded once a year. Only the growth counts as a benefit; the down payment itself is never treated as a cost on either side.
B, the balance still owed
The standard amortisation balance after k payments. Subtracting it from the grown home value gives the equity you would hold at the end of the period.
k, months held
Months in the comparison period, capped at the loan term. Once the loan is paid off the mortgage payment stops and only property tax, insurance and HOA continue.

Worked example

The values the page loads with: a 300,000 home, 20 percent down, a 30-year loan at 4.5 percent, property tax 1.2 percent of the price, insurance 1,200 a year, no HOA, rent of 1,500 a month rising 2.5 percent a year, a 5 percent return on the down payment if renting, 3 percent home appreciation, compared over 10 years.

Net cost of buying 42,965 against net cost of renting 163,927, so the tool prints that buying is cheaper by 120,962. Every figure on screen is rounded to whole currency units.

What this result is

It is a comparison of two modelled cash paths under the assumptions you typed in, not a prediction and not financial advice. Nothing here knows what your home will be worth, what rents will do, or what an invested down payment will actually return. The output is only as good as the eleven inputs above it, and the honest way to use it is to run it several times across a range you consider plausible rather than treating a single run as an answer.

What the tool does not model

A long list, and every item on it works against buying. There are no transaction costs: no closing costs, no survey or legal fees, no transfer or stamp duty, and no agent commission when the home is sold, even though the equity figure assumes you could realise the full home value. There is no maintenance or repair budget. There is no mortgage insurance for small down payments. There is no tax treatment at all, in either direction, so no mortgage interest relief and no tax on the investment growth credited to the renting side. There is no renters insurance and no moving cost. It also holds property tax, home insurance and HOA flat for the entire period, calculating property tax once from the price you enter, while rent rises every single year. That asymmetry alone tilts the comparison toward buying, so read the buying figure as an optimistic edge of the range.

The appreciation input decides the answer

On the loaded values, changing only that one field moves the result more than any other. At 0 percent appreciation the tool reports buying cheaper by 17,787; at 3 percent, by 120,962. The 103,175 gap between them is nothing but the assumed growth on a 300,000 home over ten years. Since 3 is a default this tool ships with rather than anything observed, the useful exercise is to find the appreciation rate at which the two sides meet, and then decide for yourself whether you would bet on clearing it.

Why the down payment appears on one side only

It is counted once, as the sum the renting side invests instead of spending, and only the growth it earns is credited. The buying side is not additionally charged an opportunity cost for the same money, because that would subtract it twice from the same comparison. This is also why the buying figure can go negative over long periods: after 30 years on the loaded values the loan is gone, equity of 728,179 exceeds the 641,776 ever paid out, and the tool prints a net cost of -86,403.

Common questions

Does this tell me whether I should buy a home?

No. It compares two modelled cash paths under assumptions you supply, which is a different thing from a recommendation, and it is not financial advice. It leaves out transaction costs, maintenance, mortgage insurance and all tax treatment, and it cannot weigh anything that is not a number, such as how long you actually expect to stay. Use it to see how sensitive the comparison is to the assumptions, then take the decision on wider grounds.

What does the home appreciation field do, and what should I put in it?

It compounds the home value once a year for the comparison period, and the resulting value minus the loan balance is the equity credited to the buying side. There is no correct figure to enter. The tool defaults to 3 percent, which is a starting assumption rather than a forecast. Because the result is highly sensitive to it, running the calculation at a low, a middling and a high rate is far more informative than any single number.

Why does the net cost of buying sometimes come out negative?

Because equity has grown larger than everything ever paid out. Over 30 years on the loaded values the loan is fully repaid, equity reaches 728,179 against 641,776 paid out, and the net cost prints as -86,403. That is the model working as designed, not an error, but remember it assumes the full home value could be turned into cash with no selling costs at all.

What happens if the comparison period is longer than the loan term?

The mortgage payment stops at the end of the term and only property tax, insurance and HOA continue for the remaining months. On the loaded values, extending from 30 years to 35 raises cash paid out from 641,776 to 665,776 - exactly 60 further months of the 400 a month in carrying costs, with no mortgage payment in it.

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