Introduction
Every homebuyer faces the same question: how much house can I afford? It sounds simple, but the answer depends on who you ask. A lender will give you one number. A financial planner will give you another. Your gut will give you a third.
The lender's number represents the maximum they are willing to risk. It is not necessarily the amount you should borrow. The gap between "what you can qualify for" and "what you can comfortably afford" is often the difference between a home that supports your financial life and one that consumes it.
This guide explains how affordability is calculated, the formulas lenders use, the costs that are often overlooked, and how to find a price range that fits your actual financial situation rather than a lender's risk model.
- The 28/36 rule and how lenders use debt-to-income ratios
- The true costs of homeownership beyond the mortgage payment
- How down payment and credit score affect affordability
- Why you should borrow less than the maximum approved amount
- How to calculate a realistic price range for your situation
The Two Numbers That Matter Most
Mortgage affordability comes down to two numbers: your income and your debts. Every lender evaluates these together to determine how much you can borrow .
Income
Lenders use gross monthly income — what you earn before taxes and deductions — as the baseline for affordability calculations. This includes salary, bonuses, commissions, self-employment income, and other verifiable sources.
Debt
Lenders add up all your monthly debt obligations: car loans, student loans, credit card minimums, personal loans, and the projected mortgage payment. The relationship between this total and your income determines whether the loan is approved .
The math is not complicated. What complicates it is that different lenders apply different thresholds. Some are stricter, some more lenient. Understanding the standard formulas helps you anticipate what any lender will conclude.
The 28/36 Rule Explained
The 28/36 rule is the traditional guideline for mortgage affordability. It sets two thresholds for how much of your income can go toward housing and total debt .
The front-end ratio (28%)
Your total housing costs should not exceed 28% of your gross monthly income. Housing costs include:
- Principal and interest on the mortgage
- Property taxes
- Homeowners insurance
- Private mortgage insurance (if applicable)
- HOA fees (if applicable)
The back-end ratio (36%)
Your total monthly debt payments — including housing costs plus all other debts — should not exceed 36% of your gross monthly income.
Example with $6,000 monthly gross income
- Maximum housing cost (28%): $1,680
- Maximum total debt (36%): $2,160
- Therefore, non-housing debts must stay under $480
The 28/36 rule is a guideline, not a regulation. Many lenders allow ratios above 36%, especially for borrowers with strong credit and reserves. But exceeding 36% increases financial strain and reduces your cushion for unexpected expenses .
Debt-to-Income Ratio
Debt-to-income ratio (DTI) is the primary metric lenders use to evaluate mortgage affordability. It is calculated by dividing your total monthly debt payments by your gross monthly income .
What counts as debt for DTI
- Proposed mortgage payment (principal, interest, taxes, insurance)
- Car loan payments
- Student loan payments
- Credit card minimum payments
- Personal loan payments
- Child support or alimony obligations
What does not count
- Rent or utility payments (not ongoing debt)
- Groceries, gas, and other living expenses
- Retirement contributions
- Insurance premiums other than homeowners
| DTI Range | Lender View | Typical Outcome |
|---|---|---|
| Below 36% | Strong | Best rates and terms available |
| 36% – 43% | Acceptable | Most loans approved; terms vary |
| 43% – 50% | Elevated | Approval possible for some loan types; stricter requirements |
| Above 50% | High risk | Approval unlikely with most lenders |
The True Cost of Homeownership
First-time buyers often budget only for the mortgage payment. That is a mistake. The full cost of owning a home is significantly higher than principal and interest alone .
Costs beyond the mortgage payment
- Property taxes: Typically 0.5% to 2.5% of assessed value per year, depending on location
- Homeowners insurance: Usually $800 to $2,500 per year for a median-priced home
- Private mortgage insurance (PMI): Required if down payment is less than 20%; typically 0.3% to 1.5% of loan amount annually
- HOA fees: $100 to $500+ monthly in communities with associations
- Maintenance and repairs: Budget 1% to 2% of home value annually
- Utilities: Often higher than renting due to larger space and outdoor maintenance
- Closing costs at purchase: Typically 2% to 5% of the loan amount
Example: Total monthly cost of a $350,000 home
| Expense | Estimated Monthly Cost |
|---|---|
| Principal and interest (30-year, 6.5%) | $2,212 |
| Property taxes (1.2% annually) | $350 |
| Homeowners insurance | $150 |
| PMI (with 10% down) | $130 |
| Maintenance reserve (1% annually) | $292 |
| Total monthly cost | $3,134 |
The mortgage payment is $2,212, but the true monthly cost of ownership is over $3,100. Buyers who only consider the mortgage payment often discover this gap after closing — and it strains their budget significantly.
How Down Payment Affects Affordability
The down payment does more than reduce the loan amount. It affects your monthly payment, your eligibility for certain loan programs, and whether you pay for mortgage insurance .
Down payment thresholds that matter
- Less than 20% down: Private mortgage insurance (PMI) is typically required, adding $100 to $300+ to your monthly payment
- 20% down: PMI is not required, significantly reducing monthly costs
- 3% to 5% down: Available through some conventional and FHA programs, but at higher monthly cost
- 3.5% down: Minimum for FHA loans
- 0% down: Available through VA loans for eligible veterans and USDA loans for rural properties
Example: Effect of down payment on a $350,000 home
| Down Payment | Loan Amount | Monthly P&I | PMI | Total Monthly |
|---|---|---|---|---|
| 5% ($17,500) | $332,500 | $2,101 | $277 | $2,378 |
| 10% ($35,000) | $315,000 | $1,991 | $131 | $2,122 |
| 15% ($52,500) | $297,500 | $1,880 | $62 | $1,942 |
| 20% ($70,000) | $280,000 | $1,770 | $0 | $1,770 |
Numbers assume a 30-year fixed loan at 6.5%. Moving from 5% down to 20% down reduces the monthly payment by over $600. Over the life of the loan, the savings from avoiding PMI alone total tens of thousands of dollars.
How Credit Score Affects Affordability
Your credit score determines the interest rate you are offered, which in turn affects how much house you can afford at a given monthly payment .
The rate you qualify for matters
A higher credit score unlocks lower interest rates. A lower rate means a smaller monthly payment for the same loan amount — or a larger loan amount for the same monthly payment.
| Credit Score | Typical Rate | Monthly P&I on $300,000 |
|---|---|---|
| 760+ | 6.0% | $1,799 |
| 700 – 759 | 6.4% | $1,877 |
| 660 – 699 | 6.9% | $1,976 |
| 620 – 659 | 7.5% | $2,098 |
| Below 620 | 8.0%+ | $2,201+ |
Numbers assume a 30-year fixed loan with a 20% down payment. Rates vary by lender and market conditions. The difference between the highest and lowest tier is over $400 per month on the same loan amount.
This is why improving your credit score before applying for a mortgage can be one of the highest return financial moves you can make. Paying down credit card balances, correcting credit report errors, and avoiding new credit inquiries in the months before applying can raise your score meaningfully .
Lender Maximum vs Comfortable Budget
The maximum amount a lender will approve is not the amount you should borrow. Lenders calculate affordability using formulas that do not account for your full financial life .
What lenders do not consider
- Your retirement savings goals
- Your children's education costs
- Your emergency fund needs
- Your discretionary spending priorities
- Your tolerance for financial stress
- Your long-term career or income stability
A loan that consumes 43% of your income may be approvable, but it leaves very little room for savings, emergencies, or enjoyment. That ratio works for some people and destroys the financial lives of others.
A better approach: work backward from your budget
- Calculate your monthly take-home income
- Subtract your non-negotiable expenses (food, utilities, transportation, insurance)
- Subtract savings and retirement contributions you want to maintain
- Subtract any remaining debt payments
- What remains is the amount you can genuinely afford for housing
This budget-based approach usually produces a lower number than the lender's maximum. That is the point. Borrowing below your maximum builds financial resilience and prevents your home from becoming a source of stress instead of stability.
Real Example: $80,000 Household Income
Here is how affordability plays out for a household earning $80,000 per year, or $6,667 per month gross.
Lender's maximum (28/36 rule)
- Maximum housing cost (28%): $1,867
- Other monthly debts (car loan, student loan): $500
- Maximum total debt (36%): $2,400
- Room for mortgage: $2,400 − $500 = $1,900
The lender's calculation suggests this household could afford a mortgage payment up to about $1,900. With property taxes and insurance included, that translates to a home price around $280,000 to $310,000 depending on local taxes and down payment.
Budget-based comfort analysis
Now consider the actual budget. Take-home pay is approximately $5,500 per month after taxes.
| Expense | Amount |
|---|---|
| Take-home pay | $5,500 |
| Groceries and household | $700 |
| Transportation | $450 |
| Utilities (excluding housing) | $200 |
| Insurance (health, auto, life) | $400 |
| Existing debts | $500 |
| Savings and retirement | $800 |
| Discretionary and personal | $600 |
| Remaining for housing | $1,850 |
In this example, the budget-based analysis lands close to the lender's number. But in many households, it lands significantly lower. Add childcare, elder care, or higher retirement contributions, and the affordable number drops quickly.
Use the Rent vs Buy Calculator to compare the true cost of owning versus renting in your specific market.
Calculating Your Affordable Price Range
Here is a step-by-step method for determining your affordable price range without relying only on lender formulas.
Step 1: Determine your monthly housing budget
Use the budget-based approach above. Identify the maximum monthly amount you can commit to housing without straining other financial priorities.
Step 2: Subtract taxes, insurance, and other costs
Estimate property taxes (about 1% of home value annually in many areas), homeowners insurance, PMI if applicable, and HOA fees. Subtract these from your housing budget to find what is available for principal and interest.
Step 3: Work backward to a loan amount
Given your available principal and interest payment, calculate the loan amount you can support at current interest rates. Online mortgage calculators can do this quickly.
Step 4: Add your down payment
Your maximum home price is the loan amount plus your down payment.
Step 5: Add a safety margin
Reduce the resulting price by 5% to 10%. This buffer protects you against rate increases, unexpected expenses, or income changes. A home slightly below your maximum is almost always a better decision than one that stretches your budget to the limit.
Related Calculators
Use these MoneyTool calculators to determine your affordable price range:
Authoritative Resources
For additional guidance from official sources:
- Consumer Financial Protection Bureau (CFPB): Loan Options for Homebuyers — official guidance on mortgage types, costs, and affordability.
- Consumer Financial Protection Bureau (CFPB): What Is a Debt-to-Income Ratio — explains how DTI is calculated and its role in mortgage approval.
Frequently Asked Questions
How much house can I afford on my salary? +
A common guideline is that your total housing costs should not exceed 28% of your gross monthly income, and total debt payments should not exceed 36%. Many lenders will approve loans up to 43% to 50% debt-to-income ratio. The safest approach is to calculate your affordability based on your actual budget rather than the maximum a lender will approve.
What is the 28/36 rule? +
The 28/36 rule is a mortgage affordability guideline. It states that your housing costs (principal, interest, taxes, insurance) should not exceed 28% of your gross monthly income, and total debt payments (including housing, car loans, student loans, credit cards) should not exceed 36%. Lenders often allow higher ratios, but exceeding these numbers increases financial strain.
What is a good debt-to-income ratio for a mortgage? +
Most conventional lenders prefer a debt-to-income ratio of 36% or lower. Ratios up to 43% are often acceptable for qualified mortgages. Some loan programs allow up to 50% in certain circumstances, but higher ratios mean less financial cushion. A lower ratio improves your chances of approval and better loan terms.
How much should I put down on a house? +
Twenty percent down avoids private mortgage insurance and lowers your monthly payment. However, many buyers put down less. FHA loans allow as little as 3.5% down, and some conventional loans allow 3%. A smaller down payment increases monthly costs and total interest but may make homeownership accessible sooner.
What costs besides the mortgage payment should I budget for? +
Beyond principal and interest, homeowners pay property taxes, homeowners insurance, possibly private mortgage insurance, HOA fees, maintenance and repairs, and utilities. A common guideline is to budget 1% to 2% of the home's value annually for maintenance. Total housing costs should be considered when assessing affordability, not just the mortgage payment.
Should I borrow the maximum amount the lender approves? +
Not necessarily. Lenders calculate affordability based on formulas, not on your actual lifestyle. Borrowing less than the maximum leaves room for savings, emergencies, retirement contributions, and the unexpected costs of homeownership. A home you can comfortably afford is better than a home that stretches your budget to the breaking point.
Financial & Legal Disclaimer
Educational Purposes Only. This guide is provided for informational and educational purposes only. It does not constitute financial, legal, tax, or investment advice. MoneyTool.io is not a financial advisor, and nothing in this article should be construed as a recommendation to buy, sell, or hold any financial product.
Mortgage terms, interest rates, tax rates, and insurance costs vary by lender, jurisdiction, and individual circumstances. The examples in this guide are hypothetical and intended for illustration only. Actual affordability depends on your specific financial situation, the local housing market, and the terms offered by your lender. Before making mortgage decisions, consult a qualified financial professional.