5 Ways to Calculate How Much House You Can Afford

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Particularly for those looking to buy their first home, the big question is always, “How much house can I afford.” I can still remember my wife and I trying to crunch the numbers when we bought our first home back in 1993. I was scared to death that we wouldn’t be able to afford the mortgage payments. But we did, and as the months and years went by, our mortgage payments became more manageable.

If you’re considering buying a home, it helps to have an idea of how much you can afford. It’s very important to think of this question from two different perspectives. The first is simply how big of a mortgage will you qualify for. The answer to this question depends on a lot of factors, including your income, existing debts, interest rates, credit history and your credit score. We’ll look at several calculations that most lenders use to evaluate mortgage applicants.

The second perspective is a bit more subjective–how much home do you really need? Just because you can qualify for a mortgage, doesn’t mean that you should. Banks will qualify you for as much as they possibly can given their existing underwriting policies. But just because the money is available doesn’t mean you should take it.

With that, let’s look at 5 ways to calculate how much house you can afford, beginning with a standard rule of thumb:

2.5 to 3 Times Your Annual Income

This was the basic rule of thumb for many years. Simply take your gross income and multiple it by 2.5 or 3 to get the maximum value of the home you can afford. For somebody making $100,000, the maximum purchase price would be $250,000 to $300,000.

Keep in mind that this is a very general rule of thumb, and there are several factors that will influence the results. For example, the lower the interest rate you can obtain, the higher the home value you can afford on the same income. This is one reason why your credit score is so important. A good credit score of 760 or higher can net your an interest rate that is 1.5% lower than if you had a fair score of say 620. A 1.5% lower rate can easily translate into savings of tens of thousands of dollars over the life of a mortgage.

If you don’t know your credit score, you can get your FICO score for free from one of several credit scoring companies. Also keep in mind that some suggest higher or lower multiples. I’ve seen banks recommend ratios as low as 1.5 times salary or as high as 5 times salary. I think that for most situations, a good starting point is 2.5x your income.

The 28% Front End Ratio

When banks evaluate your home loan application, one very important calculation is known as your housing expense to income ratio. Also called the front-end ratio, banks will take your projected housing expense for the home you want to buy (principal, interest, taxes and insurance) and divide by your total monthly income. Generally, mortgage companies are looking for a ratio of 28% or less.

For example, if your income is $10,000 a month, most banks will qualify you for a loan (subject to other factors, of course) so long as your total housing expenses does not exceed $2,800 each month. While the 28% mortgage to income ratio is followed by many institutions, some will qualify a borrower with a slightly higher ratio.

The 36% Rule

Even if your housing expense to income ratio is 28% or less, you still have one more hurdle to clear—the debt to income ratio. Also referred to as the back-end ratio, it takes your total monthly minimum debt payments and divides by your gross income. Debt payments include not only your projected mortgage, but also minimum credit card payments, car loan payments, school loan payments, and any other payments on debt.

Bankers typically are looking for a back-end ratio of no more than 36%, although some will go a bit higher than this. To relate both the 28% and 36% numbers, here is a chart showing the calculations for various income levels:

Gross Income
28% of Monthly Gross Income
36% of Monthly Gross Income
$20,000$467$600
$30,000$700$900
$40,000$933$1,200
$50,000$1,167$1,500
$60,000$1,400$1,800
$80,000$1,867$2,400
$100,000$2,333$3,000
$150,000$3,500$4,500

Special HFA Rules

An FHA mortgage has special rules set by the government. For the mortgage payment expense to income ratio, the percentage cannot be greater than 29%. For the back-end ratio, the maximum to still qualify for an FHA loan is 41%. Note that although FHA loans are government sponsored, you still apply for the loans through private banks and mortgage companies. If you’d like to get see current rates, check out our mortgage rates, which are updated daily.

The Dave Ramsey Mortgage

Dave Ramsey takes a very conservative approach to home buying. If you can, he believes you should pay cash for a home. But if you do have to finance the purchase, Ramsey says you should finance your home with a 15-year mortgage and that your mortgage payments, including insurance and taxes, should be no more than 25% of your take home pay. He also believes you should not buy a home until you have a 20% down payment.

If you decided to follow Dave’s approach, simply divide the amount of down payment you have available by .20. For example, if you have $25,000 saved for a down payment, the maximum amount you could spend on a home would be $125,000 ($25,000 / .20). Using this example, you’d finance $100,000 on a 15-year mortgage. At prevailing rates, and making some assumptions about insurance and taxes, the monthly payment would be about $1,000.

Of course, you’ll also need the income to handle the mortgage payments. Here is a table of your maximum monthly payment under the Dave Ramsey approach to mortgages. I’ve assumed take-home pay is 75% of gross income:

Gross Income
Monthly Take-Home
Maximum Monthly Payment
$20,000$1,250$312
$30,000$1,875$468
$40,000$2,500$625
$50,000$3,125$781
$60,000$3,750$937
$80,000$5,000$1,250
$100,000$6,250$1,562
$150,000$9,375$2,343

If you are a first-time home buyer, following Dave’s approach is going to be very difficult. Heck, it may be difficult if you are buying your second or third home. We certainly could not have bought our first or second home under these conditions, but it’s still an approach to consider.

Next –> What Credit Score Do You Need to Buy a Home

Published or Updated: July 28, 2013
About Rob Berger

Rob founded the Dough Roller in 2007. A litigation attorney in the securities industry, he lives in Northern Virginia with his wife, their two teenagers, and the family mascot, a shih tzu named Sophie.

Comments

  1. Tyler says:

    I would suggest deciding the highest monthly payment you are comfortable with for a 15 year mortgage, then getting a 30 year mortgage for that amount. The just make extra principal payments each month to bring your total monthly payment what you thought you could afford for the 15 yr.

    This allows you pay the mortgage off in about 15 years and avoid a lot of interest, but still provides you with the flexibility in the event of a job loss, emergency, or just make a desired lifestyle change in the future.

    As long as rates for the 15 year and 30 year are close this seems to be the best solution to me.

  2. kenyantykoon says:

    this is one of your more compex posts. i didnt think that there was this much to consider when buying a home. and this is just the finances, there are other things too like the neighbours and schools and stuff. i think i may rent a little longer :)

  3. Andy says:

    Don’t forget to factor in property taxes for your escrow account. They can be up to 30% of your monthly payments so are a big item to consider.

  4. Pete says:

    Your math isn’t working on some of the calculations. 28% of $50K, spread over 12 months is $1,167

    • DR says:

      Pete, thanks for letting me know.

  5. Al says:

    There is more to this problem. One must take into consideration landscaping and home maintenance.While a new home will not require much maintenance or landscaping costs initially there will eventually be large expenses such as water heater malfunction, air condtioning/ furnace replacement (most units are warrantied for 10 years, major appliances, roof replacement(usuallly last 15 to 20 years. Landscape maintenance is also very costly even if you do the work yourself. I found this out recently when I had to do all these within 2 years. I had the resources to go through this huge hit financially. So saving at least 10 % of your gross income is the solutuion.(“The Richest Man in Babylon”) Al

  6. cindy cavanaugh says:

    Me and my husband filed a chapter 7, due to medical bills and a seperation. What do we have to do to get our credit in shape or what do you suggest to be able to get a home loan. Before the chapter 7 I had outstanding credit. Could you please assist me in this matter.

  7. Troy says:

    Good post. Too many people buy huge expensive homes while living on a tiny income. I bought a house for $350k, and I make more than $100k a year (fluctuates from year to year because I’m a professional investor).

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