Buying · Financing
How much house you can afford, and why the lender's number isn't the answer
A lender's preapproval tells you the most you can borrow on paper. What you can comfortably afford to live with is usually a smaller number, and the gap between the two is where most first-time buyer regret starts.
On a $100,000 household income, the comfortable home price (36% DTI) tops out near $457000; lenders will write to $550000 (43% DTI) and call it qualifying.
PITI as a share of monthly gross income, sweeping home price from $200K to $1M with 20% down at 7.0% / 30yr. The two horizontal references are the conventional 36% comfortable threshold and the 43% lender qualifying ceiling — the gap between them is what underwriting will allow but household budgets often shouldn’t.
Source · Internal calculation · Methodology at /tools/affordability
Key takeaways
- A lender's preapproval typically allows total housing costs up to 28–31% of gross monthly income, but the comfortable budget is usually 5–10 percentage points lower.
- Total debt-to-income (DTI) including auto, student, and credit-card debt is generally capped at 36–43% by underwriting; FHA and VA stretch higher than conventional.
- The full housing payment (PITI) includes principal, interest, property tax, homeowners insurance, HOA dues, and PMI when down payment is under 20%, not just the mortgage payment alone.
- Closing costs typically run 2–5% of the purchase price for buyers, on top of the down payment.
Quick answers
- How much house can I afford?
- A common rule of thumb is that total monthly housing costs (principal, interest, taxes, insurance, and HOA) shouldn't exceed 28–31% of gross monthly income, with all monthly debts combined under 36–43%. Lender preapproval often allows higher ratios than what's actually comfortable to live with, the comfortable budget and the qualifying budget are two different numbers.
- What's the difference between a lender's preapproval and what I can comfortably afford?
- Lender preapproval is the maximum a lender will let you borrow based on income, debts, and credit. Comfortable affordability factors in saving, emergencies, lifestyle, and future life changes. Lenders often preapprove higher amounts than borrowers can comfortably maintain, and anchoring to the preapproval number tends to produce stretched budgets in the first few years of homeownership.
- How much should I have saved before buying a home?
- Beyond the down payment (3–20% of price depending on loan program), buyers typically need 2–5% of the purchase price for closing costs, plus a maintenance reserve (industry guidance suggests 1–3% of home value annually). A common total cash position is the down payment plus six months of full housing payments held in reserve.
How much house a buyer can afford has three different answers: the maximum a lender will lend on paper, the monthly payment that fits comfortably in a household budget, and the all-in cost of ownership over time after taxes, insurance, maintenance, and the opportunity cost of the down payment. The three numbers are usually meaningfully different, and the gap between them is where most first-time buyer regret starts.
The first is the lender's number: the most they're willing to underwrite based on the borrower's income, credit, debts, and down payment. The second is the comfortable monthly number: a payment the household can absorb without compromising savings, retirement contributions, or general financial elasticity. The third is the target home price that produces that comfortable monthly number, after factoring in the loan, the rate, and the property-specific carrying costs.
Most first-time buyer regret comes from anchoring on the lender's number and discovering, somewhere around month four of homeownership, that it doesn't leave room for the rest of life.
What the lender is actually computing
A mortgage underwriter looks at two ratios.2 The front-end ratio is the proposed monthly housing payment (PITI plus HOA) divided by gross monthly income. The back-end ratio, usually the binding one, is total monthly debt payments, including the new mortgage, plus car loans, student loans, credit-card minimums, child support, and any other recurring debt, divided by gross monthly income.
Conforming conventional loans typically allow back-end ratios up to about 43%, with some flexibility above and below depending on credit profile and reserves.3 FHA can go higher in some scenarios. VA uses a different residual-income test on top of DTI. The actual maximum varies by program and by lender overlays.
A buyer with $9,000 in gross monthly income and $400 in non-housing debts could in principle qualify for a housing payment around $3,470, that's the 43% back-end limit. Whether $3,470 a month is a sustainable housing payment for that household is a different question and not one the underwriter is asking.
What "comfortable" actually has to absorb
A monthly housing payment doesn't sit alone. It pushes against:
- Retirement contributions (the 10–15% of income most financial planners flag as the long-run priority).
- Emergency reserves (3–6 months of expenses, ideally separate from down-payment savings).
- Maintenance, which homeowners consistently underestimate. The conventional rule of thumb is 1–2% of home value per year, averaged over time. Some years are zero. Some years are a $14,000 roof.
- Variable costs that aren't in the rate sheet: HOA dues if the home is in one, snow removal, lawn care, security, the heating bill on a 4,000-square-foot house in Minnesota.
- The non-financial flexibility cost: a higher monthly payment makes job transitions, family changes, or career risks more constrained.
The CFPB's general guidance suggests starting from a target of about 28% of gross income on housing, and back-into the home price from there.1 That number isn't a rule. It's a starting point for a conversation about what the household values. A two-earner couple with high job security and a big bonus structure may be comfortable at 35%. A single-earner household in a volatile industry may want to be at 22%.
How the affordability calculator gets to a number
The affordability calculator at /tools/affordability runs a binary search to find the largest home price where the resulting PITI payment fits both an income constraint (DTI) and a cash constraint (down payment plus closing costs versus available savings). The result is the maximum affordable home price under those constraints, the same calculation a lender's automated underwriting engine performs, with the same inputs.
The calculator surfaces three sensitivity dials prominently (DTI ratio, mortgage rate, and term) because small changes in any of them shift the maximum home price by tens of thousands of dollars. A buyer who can comfortably afford $620,000 at 35% DTI can afford about $560,000 at 30% DTI on the same income. The DTI dial is one of the most useful sensitivity tests, because most buyers haven't sat with the question of which percentage of their income they actually want to commit to housing.
A frame for the conversation
The most useful way to think about affordability is as a budget choice rather than a borrowing-capacity question. The starting questions are roughly:
- What monthly housing payment leaves room for retirement, reserves, and the kinds of variability life brings?
- What home price, at current rates and a realistic down payment, produces that monthly?
- How does that price compare to the lender's maximum, and what does the difference mean for the search?
The answer to (3) is sometimes "a much smaller home in this market." That's a hard answer. It's also the one that most often correlates with people enjoying their house five years after they bought it.
Frequently asked
How much house can I afford?
A common rule of thumb is that total monthly housing costs (principal, interest, taxes, insurance, and HOA) shouldn't exceed 28–31% of gross monthly income, with all monthly debts combined under 36–43%. Lender preapproval often allows higher ratios than what's actually comfortable to live with, the comfortable budget and the qualifying budget are two different numbers.What's the difference between a lender's preapproval and what I can comfortably afford?
Lender preapproval is the maximum a lender will let you borrow based on income, debts, and credit. Comfortable affordability factors in saving, emergencies, lifestyle, and future life changes. Lenders often preapprove higher amounts than borrowers can comfortably maintain, and anchoring to the preapproval number tends to produce stretched budgets in the first few years of homeownership.How much should I have saved before buying a home?
Beyond the down payment (3–20% of price depending on loan program), buyers typically need 2–5% of the purchase price for closing costs, plus a maintenance reserve (industry guidance suggests 1–3% of home value annually). A common total cash position is the down payment plus six months of full housing payments held in reserve.Does my credit score affect how much house I can afford?
Credit score affects the interest rate, which in turn affects what monthly payment a given loan amount produces. Higher scores (760+) typically qualify for the best advertised rates; lower scores produce higher rates and reduce purchasing power on the same income. FHA and VA programs accept lower credit scores than conventional conforming loans.What is the 28/36 rule?
The 28/36 rule is a traditional underwriting guideline suggesting that monthly housing costs (PITI plus HOA) stay under 28% of gross monthly income, and total monthly debt payments stay under 36%. Modern lenders often allow higher ratios (up to 43% or 50% on some programs) but the 28/36 framing remains a useful comfort threshold separate from the qualifying maximum.