Home / Financial / House Affordability Calculator
House Affordability Calculator: How Much Home Can You Afford?
Enter your income, monthly debts, savings for a down payment and the loan terms. The calculator works backwards from your chosen ratio limits to the highest home price whose full monthly cost still fits.
How the maximum price is found
Lenders commonly test two ratios against gross (pre-tax) monthly income. The front-end ratio caps the housing payment alone. The back-end ratio caps the housing payment plus every other monthly debt. The calculator turns each ratio into a monthly dollar limit, then uses the smaller of the two as the housing budget.
The budget has to cover four parts: principal and interest, property tax, insurance, and any association fees. Principal and interest depend on the loan, the loan depends on the price minus your down payment, and tax depends on the price, so the price appears on both sides of the equation. Solving it algebraically gives:
Price = (Budget − Insurance/12 − Fees + Down × k) ÷ (k + t)
where k is the monthly payment on a loan of 1 at your rate and term (the annuity factor), and t is the property tax rate divided by 1200. No guessing or repeated trial is needed.
Why the ratio limits are editable
A 28% front-end and 36% back-end pair is a long-standing rule of thumb, but it is not a law. Lenders, loan programmes and countries use different limits, and some allow noticeably higher back-end ratios for strong applicants. Rather than hard-coding any figure, the two limits above are inputs. Enter the numbers your lender quotes, or try stricter ones if you want a safety margin.
Try the exercise of lowering the housing limit from 28% to 22%. The affordable price falls sharply because the same budget has to fund interest, tax and insurance. The result also tells you which of the two ratios is binding. If it is the total-debt limit, paying off a car loan or card balance can raise your affordable price more than a larger down payment would.
Costs the ratios do not capture
- Maintenance and repairs. A common planning allowance is one to two percent of the home value per year, but older homes may need more.
- Utilities and commuting. A larger or more remote home often raises both.
- Closing costs. These come out of cash on top of the down payment, so keep savings beyond the amount entered here.
- Rate changes. If your loan is adjustable, test a higher rate.
- Income stability. Ratios use today's income; a variable or single income deserves a bigger margin.
Limits of this estimate
This tool uses a single fixed rate with level monthly payments and treats property tax as a flat percentage of the price. Real tax bills depend on local assessment, and insurance varies by property. Lenders also look at credit history, savings reserves and employment. Treat the price as a ceiling for browsing, not as a recommended spending target, and compare it with what the mortgage calculator shows for a specific home. For an exact figure, ask a lender for a written pre-approval.
Worked example
A household earning 120,000 a year with 500 a month in other debts, 60,000 saved and a 6% thirty-year loan.
Inputs
| Gross income per year | 120000 |
|---|---|
| Other monthly debt payments | 500 |
| Cash for the down payment | 60000 |
| Annual interest rate | 6 % |
| Loan term | 30 years |
| Housing cost limit (front-end ratio) | 28 % of gross income |
| Total debt limit (back-end ratio) | 36 % of gross income |
| Property tax per year | 1.2 % of home price |
| Home insurance per year | 1200 |
| Association or service fees per month | 0 |
Result
The housing-cost limit is the one that limits you.
The loan is above 80% of the price, so many lenders would add mortgage insurance or charge more.
| Loan amount | 377,385 |
|---|---|
| Principal and interest per month | 2,262.61 |
| Property tax per month | 437.39 |
| Insurance and fees per month | 100.00 |
| Total housing cost per month | 2,800.00 |
| Limit from housing ratio | 2,800.00 |
| Limit from total-debt ratio | 3,100.00 |
| Loan-to-value | 86.3% |
- Being able to qualify is not the same as being comfortable. Maintenance, utilities and savings are not in these ratios.
Financial disclaimer: Results are estimates for planning and education. They are not financial, tax or legal advice. Fees, taxes, rates and rules vary by lender, product and country, so confirm figures with your provider or a qualified adviser before making decisions.
Frequently asked questions
How much house can I afford on my income?
It depends on your debts, down payment, interest rate and the ratio limits you apply. This calculator finds the price at which your housing cost equals the smaller of the housing-ratio limit and the total-debt limit.
What is the front-end ratio?
It is the monthly housing cost (loan payment, property tax, insurance and fees) divided by gross monthly income. Lenders set a maximum, and you can edit it above.
What is the back-end ratio?
It is all monthly debt payments, including the new housing cost, divided by gross monthly income. It stops a home payment that looks fine on its own from sitting on top of heavy existing debts.
Does a bigger down payment raise the price I can afford?
Yes, because less has to be borrowed, so more of the monthly budget is left for the price. The effect is largest when the down payment is small relative to the price.
Should I spend the full amount shown?
Not necessarily. The result is a ceiling based on ratios. Many buyers choose a lower price to keep room for repairs, savings and changes in income.
Related calculators
References and sources
- Consumer Financial Protection Bureau: educational material on buying a home and debt-to-income ratios. Link
- Standard annuity (level payment) formula from introductory finance texts.