Home Affordability Calculator – How Much House Can You Afford?
Our home affordability calculator helps you determine how much house you can afford based on your income, existing debts, down payment, and current mortgage rates. By analyzing your debt-to-income ratio alongside estimated property taxes and insurance, it gives you a realistic maximum home price to guide your search. Whether you're a first-time buyer or upgrading, understanding your budget before you shop can save you time and prevent financial stress.
Your total household gross income before taxes per year.
Total monthly payments for car loans, student loans, credit cards, etc.
The amount of cash you plan to put down upfront.
Current mortgage interest rate. Check with your lender for the latest rates.
The number of years over which you'll repay the mortgage.
Average U.S. property tax rate is around 1–1.5% of home value per year.
Estimated annual homeowner's insurance premium.
Lenders typically allow up to 43% DTI. Lower is safer for your budget.
Your results will appear here
How to Use This Calculator
1. Enter your annual household gross income before taxes. 2. Input your total existing monthly debt payments, such as car loans, student loans, and minimum credit card payments. 3. Enter how much cash you plan to put toward a down payment. 4. Fill in the current annual mortgage interest rate — check with your lender or browse online for today's rates. 5. Select your preferred loan term (10, 15, 20, or 30 years). 6. Optionally enter your local property tax rate and estimated annual home insurance cost for a more accurate total monthly payment. 7. Choose your maximum debt-to-income ratio — 43% is the standard lender limit, while 36% is more conservative. 8. Click Calculate to see your maximum home price, estimated monthly payment, and DTI ratios instantly.
How Home Affordability Is Calculated
Lenders use your debt-to-income (DTI) ratio as the primary measure of how much mortgage you can handle. Your DTI is the percentage of your gross monthly income that goes toward all monthly debt payments, including the proposed housing payment.
Back-End DTI Ratio
The back-end DTI includes all monthly debts — housing costs plus car loans, student loans, credit cards, etc. Most conventional lenders cap this at 43%, though some loan programs allow up to 50% with strong compensating factors.
- 36% or below: Conservative and ideal — you'll have strong approval odds and more financial cushion.
- 43%: The standard maximum for most conventional mortgage programs.
- 50%: Possible with FHA loans or strong credit, but leaves little room for unexpected expenses.
Front-End DTI Ratio
The front-end ratio (also called the housing ratio) measures only your housing costs — principal, interest, taxes, and insurance (PITI) — as a percentage of gross income. Lenders typically prefer this to be 28% or below.
The Affordability Formula
Our calculator works backward from your chosen maximum DTI to find the largest loan amount whose monthly payment (plus taxes and insurance) keeps you within your budget:
- Max Total Monthly Debt = DTI% × Monthly Gross Income
- Max Housing Payment = Max Total Monthly Debt − Existing Monthly Debts
- Available for P&I = Max Housing Payment − Monthly Insurance − Monthly Property Tax
- Max Loan = Available for P&I ÷ (Mortgage Payment Factor + Tax Rate Factor)
- Max Home Price = Max Loan + Down Payment
Monthly Mortgage Payment (P&I)
The principal and interest portion of your payment is calculated using the standard amortization formula:
M = P × [r(1+r)^n] / [(1+r)^n − 1]
Where P is the loan principal, r is the monthly interest rate, and n is the total number of monthly payments.
Other Factors to Consider
While our calculator covers the main financial variables, your actual buying power also depends on:
- Credit score: Higher scores unlock lower interest rates, directly increasing affordability.
- Private Mortgage Insurance (PMI): Required if your down payment is less than 20%, adding 0.5–1.5% of the loan annually to your costs.
- HOA fees: Monthly homeowners association fees count as housing costs and reduce the loan amount you can afford.
- Loan type: FHA, VA, USDA, and conventional loans have different DTI limits and qualification requirements.
- Emergency fund: Lenders may require 2–6 months of mortgage payments in reserves after closing.