Financial Planning | June 2, 2026 | Capstag.com | 9 min read
Every mortgage calculator will tell you how much house you can afford. The problem is that lender approval limits and genuine financial comfort are two completely different numbers — and most affordability calculators optimise for the first, not the second. Buying at the top of what a lender approves is one of the most reliable paths to being house-poor: technically a homeowner, practically unable to save, invest, or handle any financial disruption without stress. This article covers the real calculation — the one that keeps your finances intact after the keys are in your hand.
Quick Answer: How much house you can afford depends on income, debt, down payment, and ongoing costs — not just the mortgage payment. The 28/36 rule is the standard: housing costs should not exceed 28% of gross monthly income, and all debt payments combined should not exceed 36%. At current mortgage rates of approximately 6.33% (30-year fixed), a $100,000 annual income supports a home price of approximately $350,000–$380,000 with a 10–20% down payment and modest existing debt. Lenders may approve $450,000+ — but that approval is not a recommendation.
How much mortgage you can afford is one of the highest-stakes financial calculations you will ever run — and one of the most frequently done wrong. The version lenders run maximises what they will lend. The version you should run maximises your long-term financial health and flexibility. From a financial planning perspective, the right home price is the one where the housing cost allows you to simultaneously fund an emergency fund, retire contributions, and absorb normal homeownership surprises without depleting your savings every time something breaks.
This article connects directly to the full home buying process in how to buy your first home and the down payment calculation in how much down payment you really need.
What is the 28/36 rule for mortgage affordability?
The 28/36 rule is the most widely used mortgage affordability standard among financial planners and conservative lenders. It sets two limits simultaneously. The first limit: total monthly housing costs — including mortgage principal, interest, property taxes, homeowner's insurance, and HOA fees — should not exceed 28% of gross monthly income. The second limit: all monthly debt payments combined, including the new mortgage and all existing debts (car loans, student loans, credit cards), should not exceed 36% of gross monthly income. The rule exists to preserve disposable income for retirement savings, emergency reserves, and normal living costs after housing is paid.
| Annual Income | Monthly Gross | 28% Max Housing | 36% Max Total Debt | Affordable Home Price* |
|---|---|---|---|---|
| $60,000 | $5,000 | $1,400 | $1,800 | ~$215,000 |
| $75,000 | $6,250 | $1,750 | $2,250 | ~$270,000 |
| $100,000 | $8,333 | $2,333 | $3,000 | ~$360,000 |
| $125,000 | $10,417 | $2,917 | $3,750 | ~$450,000 |
| $150,000 | $12,500 | $3,500 | $4,500 | ~$545,000 |
*Estimated home price based on 6.33% 30-year fixed rate, 20% down payment, with property taxes and insurance at 1.5% of home value annually.
Why lender approval limits are not the same as what you can afford
Mortgage lenders approve loans based on debt-to-income ratios up to 43–45% of gross income — significantly higher than the 28/36 conservative standard. A household earning $100,000 annually could receive approval for a mortgage where total housing costs reach $3,750/month — 45% of gross income. What that approval does not account for: retirement contributions (10–15% of gross income for long-term financial security), the federal and state income tax that reduces the $100,000 gross to approximately $72,000–$78,000 net, savings and emergency fund contributions, childcare, healthcare costs, or any of the dozens of regular expenses that do not appear on a mortgage application. Buying at 45% of gross income on a $100,000 salary typically leaves $2,000–$2,500/month for all other living expenses, retirement, and savings combined — a constraint that most buyers do not feel until month three of ownership when the first repair bill arrives.
The house-poor trap: According to the Consumer Financial Protection Bureau, homeowners who allocate more than 30% of gross income to housing are significantly more likely to miss mortgage payments during income disruptions. Buying at 28% creates meaningful buffer. Buying at 43% leaves almost none. The mortgage payment that felt manageable at approval becomes a source of monthly stress when property taxes increase, insurance premiums rise, or an appliance needs replacement.
The five costs that kill affordability after purchase
Most affordability calculations include only the mortgage payment — sometimes property taxes and insurance, almost never all five of the costs that determine whether homeownership is actually comfortable on your income.
Property taxes vary dramatically by state and county. According to Tax Foundation data, effective property tax rates range from 0.28% of home value annually (Hawaii) to 2.47% (New Jersey). On a $400,000 home, this means $1,120/year in Hawaii versus $9,880/year in New Jersey — a difference of $739/month in housing cost that does not show up in most online calculators unless you manually enter your state's rate.
Homeowner's insurance averages approximately 0.64% of home value annually nationally, but high-risk areas (flood zones, hurricane regions, fire-prone areas) can cost 2–4% or more. PMI adds 0.46–1.5% of the loan amount annually for buyers who put less than 20% down. HOA fees in managed communities average $250–$800/month. And routine maintenance — the cost that surprises almost every first-time buyer — averages 1–2% of home value annually, meaning a $400,000 home costs $4,000–$8,000/year just to maintain at baseline. Budget $333–$667/month for this category and never touch it for non-home purposes.
How to calculate what you can genuinely afford — the real method
1 |
Start with take-home pay, not gross incomeMortgage affordability calculators use gross income. You live on net income. Calculate your actual monthly take-home pay after all taxes and payroll deductions. This is your real starting number — not the gross figure the lender uses. |
2 |
Subtract all fixed monthly obligationsList every current monthly obligation: car payment, student loans, credit cards (minimum payments), subscriptions, childcare, insurance premiums, and any other fixed cost. Subtract the total from take-home pay. The remaining number is available for housing and variable living costs. |
3 |
Reserve for savings, retirement, and emergency fundDeduct your target monthly savings rate — minimum 15% of gross income for retirement, plus $200–$500/month for emergency fund building. These are non-negotiable financial commitments that should not be sacrificed for a larger house. Whatever remains is genuinely available for housing. |
4 |
Calculate ALL housing costs, not just the mortgage paymentFor any home you are evaluating: add mortgage payment + property tax estimate for that county + homeowner's insurance estimate + PMI if applicable + HOA if applicable + $300–$600/month maintenance reserve. This total is the true monthly cost of owning that home. Compare it against the amount remaining from Step 3. |
What home price can I afford on my salary — common salary scenarios
| Salary | 28% Rule Max Housing | Home Price (20% Down) | Home Price (10% Down) | Note |
|---|---|---|---|---|
| $50,000/yr | $1,167/mo | ~$175,000 | ~$160,000 | Very tight in most markets |
| $75,000/yr | $1,750/mo | ~$265,000 | ~$245,000 | Workable in mid-cost markets |
| $100,000/yr | $2,333/mo | ~$355,000 | ~$325,000 | Solid range in most markets |
| $120,000/yr | $2,800/mo | ~$430,000 | ~$395,000 | Comfortably buys median home |
| $150,000/yr | $3,500/mo | ~$540,000 | ~$495,000 | Strong buying power nationally |
The mortgage stress test — what happens if rates rise or income drops
Before committing to any home price, run a stress test: what does your housing situation look like if mortgage rates rise 1–2 percentage points (for ARM buyers), your income drops 15–20% due to a job change or economic downturn, or a major home repair ($10,000–$25,000) is needed in year one? If any of these scenarios would make your mortgage unmanageable or force you to stop contributing to retirement entirely, the home is priced beyond your true comfort level — regardless of what the lender approved.
Conclusion
How much house you can afford is not determined by a lender's approval ceiling — it is determined by your actual take-home income, your existing obligations, your savings requirements, and the true total cost of owning that specific property in that specific location. The 28/36 rule provides the standard benchmark. Your personal cash flow analysis provides the actual answer. The home that lets you continue investing, saving, and handling normal financial surprises without stress is the right home for your finances — not necessarily the largest home the lender will fund. Read next: how much down payment do you really need?
🔑 Key Takeaways
- The 28/36 rule is the standard: housing costs should not exceed 28% of gross monthly income, and total debt payments (including mortgage) should not exceed 36%. This is more conservative than the 43–45% DTI lenders may approve — deliberately so.
- At current mortgage rates of approximately 6.33% (30-year fixed), a $100,000 annual income supports approximately $350,000–$380,000 in home price using the 28% rule with a 10–20% down payment and modest existing debt.
- Lender approval at 43–45% DTI on a $100,000 salary leaves approximately $2,000–$2,500/month for retirement, savings, and all living expenses combined after taxes. This is the definition of house-poor — avoid it deliberately.
- The five real housing costs to include in every affordability calculation: mortgage payment, property taxes (0.28–2.47% of home value by state), homeowner's insurance (~0.64%), PMI if applicable, HOA if applicable, and 1–2% annual maintenance reserve.
- Run a personal cash flow calculation — start with take-home pay, subtract fixed obligations and savings targets, and compare what remains against the true all-in monthly cost of the specific property you are considering.
- Stress-test every home price: can you handle a 15–20% income reduction, a $15,000 repair in year one, or rising property taxes without stopping retirement contributions or depleting emergency savings? If not, the price is too high for your financial situation.
Frequently Asked Questions
On a $100,000 annual salary, the 28% rule allows approximately $2,333/month for total housing costs (mortgage + taxes + insurance). At current 30-year fixed rates of approximately 6.33% with a 20% down payment, this supports a home price of approximately $350,000–$380,000, assuming property taxes and insurance at approximately 1.5% of home value annually. With a 10% down payment and PMI added, the supportable price drops to approximately $315,000–$340,000. A lender may approve a significantly higher amount — potentially $430,000–$450,000 — based on 43–45% DTI. That approval is not a recommendation to spend it. The 28% calculation is the one that keeps other financial goals intact.
The 28/36 rule sets two simultaneous limits on housing and total debt costs relative to gross monthly income. The 28 side: total monthly housing costs (mortgage principal and interest, property taxes, homeowner's insurance, PMI if applicable, HOA if applicable) should not exceed 28% of gross monthly income. The 36 side: all monthly debt payments combined — mortgage plus car loans, student loans, credit cards, and other obligations — should not exceed 36% of gross monthly income. The gap between 28% and 36% is the buffer for existing non-housing debts. If you have no other debts, you have the full range from 28% to 36% available for housing. If you have significant existing debt, your housing payment may need to be considerably below 28% to keep total debts under 36%.
On a $70,000 salary, gross monthly income is approximately $5,833. The 28% rule allows $1,633/month for total housing costs. At 6.33% on a 30-year fixed with 20% down, this supports a home price of approximately $245,000–$265,000 including property taxes and insurance estimates. With 10% down and PMI, the supportable price is approximately $225,000–$245,000. In markets where median home prices are $400,000+, a $70,000 salary creates meaningful affordability challenges without a large down payment, dual income, or significant geographic flexibility. First-time buyer programmes with down payment assistance and FHA loans at 3.5% down can help reduce the cash required, though the monthly payment burden remains tied to the purchase price and rate.
Lenders calculate mortgage qualification using your debt-to-income ratio (DTI) — total monthly debt payments divided by gross monthly income. Most conventional lenders approve DTIs up to 43%; some programmes allow up to 50% with compensating factors like high credit scores or large reserves. They also consider your credit score (higher scores unlock better rates and sometimes higher DTIs), the loan-to-value ratio (down payment size), employment history (typically two years of consistent income required), and asset reserves. The lender's calculation is purely about risk management — will you default? It does not account for whether 43% DTI leaves you enough to actually live comfortably on your net income after taxes.
No — and this is one of the most important decisions in the home buying process. The maximum lender approval is a risk threshold, not a recommendation. Buying at 43–45% DTI means that 43–45% of gross income goes to debt payments — but gross income includes income tax, which you cannot spend. After taxes, 43% of gross can become 55–60% of net income committed to debt. This leaves very little for retirement savings, emergency fund growth, or the inevitable home repairs that arrive in the first year of ownership. The 28% gross income rule for housing costs is deliberately conservative — and for most buyers, genuinely comfortable. The extra house bought by spending 15 percentage points more of income is rarely worth the financial constraint it creates.
This article is for informational purposes only and does not constitute financial advice. Mortgage rates, qualification requirements, and programmes vary by lender and location. Consult a qualified mortgage professional before making home purchase decisions.
