How Much House Can You Afford on a $100,000 Salary?
A $100,000 salary supports a very different mortgage depending on your other debts, down payment and how much of your budget you are willing to give to housing. Here is the math lenders actually use.
A six-figure salary sounds like it should settle the question. It does not. The same $100,000 income can support a $300,000 house or a $650,000 house depending on three things: how much debt you already carry, how much cash you bring to the closing table, and how much of your monthly budget you are willing to hand to a mortgage.
Lenders answer the question with ratios. You should answer it with a budget. The two numbers are rarely the same, and the gap between them is where people get into trouble.
The 28/36 rule lenders use
Most conventional lenders follow guidelines that come from Fannie Mae and Freddie Mac. The two ratios that matter are the front-end and back-end ratio.
- Front-end ratio: housing costs divided by gross monthly income. The guideline is 28 percent or less.
- Back-end ratio: all debt payments, including the mortgage, divided by gross monthly income. The guideline is 36 percent, though automated underwriting will often go to 43 or even 50 percent with compensating factors.
Housing costs mean principal, interest, property taxes, homeowners insurance, and any HOA dues. Also PMI if you put less than 20 percent down. That full package is what the ratio measures, not just the principal and interest payment.
Running the numbers on $100,000
Gross monthly income is $8,333. Twenty-eight percent of that is $2,333. That is your maximum housing payment under the front-end guideline.
Now subtract the parts that are not the mortgage. Assume $350 a month in property taxes, $125 in homeowners insurance, and no HOA. That leaves roughly $1,858 for principal and interest.
| Rate | Max loan at $1,858/mo | 30-year term |
|---|---|---|
| 6.0% | $309,900 | Payment $1,858 |
| 6.5% | $293,800 | Payment $1,857 |
| 7.0% | $279,000 | Payment $1,856 |
| 7.5% | $265,200 | Payment $1,854 |
Add a 20 percent down payment and a $294,000 loan at 6.5 percent corresponds to a purchase price near $368,000. Put 10 percent down instead and the price falls to about $326,000 before you even account for PMI, which eats further into the budget.
Why your existing debt changes everything
The back-end ratio is where car loans, student loans and credit cards show up. Suppose you have a $450 car payment, $300 in student loans and $150 in minimum credit card payments. That is $900 a month in obligations before the mortgage.
At a 43 percent back-end ratio, total debt can be $3,583. Subtract the $900 and housing gets $2,683, comfortably above the front-end limit, so the front-end rule still governs. But add a second car loan and the back-end ratio becomes the binding constraint, and the affordable price drops sharply.
What you can afford versus what you should borrow
Qualifying for a loan is not the same as being comfortable in it. A lender does not know that you are saving for a wedding, expecting a child, or funding a parent's care. The 28/36 rule is a ceiling for underwriting, not a target for living.
- Keep six months of expenses in cash after closing. Closing costs and moving expenses always exceed expectations.
- Budget for maintenance at about 1 percent of the home value per year. On a $400,000 house that is $4,000 annually, or $333 a month, and it is not in any lender calculation.
- Expect property taxes and insurance to rise. Both have outpaced inflation in most markets over the past decade.
- Consider the commute. A cheaper house further out can cost more overall once transportation is counted.
The bottom line
On a $100,000 salary with modest debt and 20 percent down, a purchase price in the $350,000 to $400,000 range is the reasonable outer edge in a 6.5 percent rate environment. With significant existing debt or a smaller down payment, the number drops quickly. Run your own figures with real taxes and insurance before you tour anything. The listing price tells you almost nothing about the monthly cost.