Why might a lender approve a mortgage that feels too big for your budget?
You get pre-approved for a mortgage, and the number is higher than you expected. It’s tempting to read it as confirmation that you can afford that much. But many people find that a payment that fits a lender’s rules feels tight once real life is added back in. That isn’t a contradiction. The lender and you are answering different questions.
What a lender is measuring
A lender’s main question is whether you’re likely to repay the loan. One of the most important tools for answering it is your debt-to-income ratio: your monthly debt payments divided by your gross monthly income, before taxes.
Common reference points are 28% of gross income for housing and 36% for all debts combined, though many loan programs allow considerably more, often up to 43% to 50%, depending on credit, savings and the type of loan.
The same rules, from your side
Imagine someone earning $100,000 a year. Their gross monthly income is about $8,333. At 28%, a lender’s guideline would allow about $2,333 a month for housing. At 36% for all debts, with a $400 car payment, it would allow up to $2,600 for housing.
Now look at that from the perspective of their bank account. After federal income tax, Social Security and Medicare, and a 5% 401(k) contribution, their take-home pay is about $6,273 a month before state income tax. In a state with a moderate income tax, it might be closer to $6,000.
A $2,600 housing payment is about 31% of gross income, but more than 40% of take-home pay. Add the car payment and they’ve committed about half of what actually reaches their account before buying groceries or paying for utilities.
What the ratio leaves out
Debt-to-income ratios count debts. They don’t count most of the costs of living.
Childcare can cost as much as a second mortgage, but it isn’t a debt. Neither are groceries, utilities, insurance, commuting, medical costs or the money you set aside for retirement. Home maintenance isn’t counted either, even though it’s a predictable cost of owning.
Lenders also can’t see what you value. If you want to keep saving for retirement, travel to see family, or have room for an unexpected expense, the approval amount doesn’t account for it.
None of this makes lenders careless. Their guidelines are designed to estimate the risk of default across many borrowers, not to plan one household’s budget. That part is yours.
Finding your own number
A more personal approach starts with your take-home pay. List what you spend on everything except housing, include what you want to keep saving, and see what’s left. That remainder, minus a margin for surprises, is the housing payment that fits your life.
Then work backward to a price. Remember that the housing payment includes property tax, insurance, any HOA dues and PMI if you put down less than 20%, plus a maintenance allowance that the lender won’t ask about.
If your own number is lower than the approval, that’s not a failure to keep up. It’s a decision to keep the rest of your life working.
Tools that can help
The debt-to-income calculator shows your ratios the way lenders see them. The home affordability calculator estimates a price range from lender guidelines, and the 50/30/20 budget calculator starts from take-home pay, which makes it a useful check against the lender’s number. For a fuller picture of monthly costs, see what it really costs to own a home.
The takeaway
A pre-approval tells you the most a lender is willing to lend, not the most you should borrow. The comfortable number comes from your take-home pay and your priorities, and it’s worth knowing before you start touring homes.
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This article is general education about US personal finance, based on the assumptions and sources described in it. It isn’t financial, tax or legal advice, and examples use hypothetical people and figures.