🏡 Home Affordability Calculator
By ToolNimba Finance Team · Reviewed by ToolNimba Editorial Review, personal finance content · Updated 2026-06-19
This calculator gives a rough estimate based on the 28/36 rule and the figures you enter. It is not a loan offer, a pre-approval, or financial advice. Lenders weigh your credit score, employment history, exact debt-to-income ratio, property taxes, insurance, mortgage insurance (PMI) and reserves, so the amount you actually qualify for can be higher or lower. Confirm any home-buying budget with a licensed mortgage lender or qualified financial adviser before making an offer.
This home affordability calculator estimates the house price you can comfortably afford using the well-known 28/36 rule. Enter your gross annual income, your existing monthly debt payments, your planned down payment, the mortgage interest rate and the loan term. The tool caps your monthly housing payment at 28% of your gross monthly income (and your total debt at 36%), then works backward from that payment to the loan and the home price you can support.
What is the Home Affordability Calculator?
The 28/36 rule is a guideline lenders have used for decades to judge whether a borrower can handle a mortgage. The first number, 28%, is the front-end ratio: your total monthly housing payment (principal, interest, property tax, home insurance and any HOA dues) should not exceed 28% of your gross monthly income. The second number, 36%, is the back-end ratio: all of your monthly debt payments combined (the housing payment plus car loans, student loans, credit card minimums and similar) should not exceed 36% of gross monthly income. Your affordable payment is whichever of these two limits is lower.
Once the calculator knows your maximum housing payment, it has to separate the part that pays the mortgage from the part that covers taxes and insurance. It sets aside an estimated percentage of the home price each year for property tax, insurance and HOA, then treats the rest of the allowable payment as principal and interest. Using the standard mortgage formula in reverse, it converts that monthly principal-and-interest figure into a loan balance, and adds your down payment to arrive at the home price you can afford.
A few things shift the answer more than people expect. A larger down payment raises the price you can reach because it adds directly to the price on top of the loan you can carry. A higher interest rate lowers it sharply, because more of each payment goes to interest rather than buying house. And existing debts matter through the 36% back-end limit: every $100 of monthly debt payment can knock several thousand dollars off the home price you qualify for. The rule is deliberately conservative, it is about what is sustainable, not the absolute maximum a lender might stretch to approve.
When to use it
- Setting a realistic price ceiling before you start browsing listings or talk to an agent.
- Seeing how paying down a car loan or credit card first would raise the home price you qualify for.
- Comparing how much more (or less) house you could afford if mortgage rates rise or fall.
- Working out how big a down payment you need to reach a target home price.
How to use the Home Affordability Calculator
- Enter your gross annual income (before tax), combining both incomes if you are buying jointly.
- Enter your total existing monthly debt payments, such as car loans, student loans and minimum card payments.
- Enter the down payment you plan to make.
- Enter the mortgage interest rate, loan term in years, and an estimate for annual tax, insurance and HOA as a percent of the home price.
- Read off the affordable home price, your maximum monthly housing payment, and the loan amount.
Formula & method
Worked examples
You earn $80,000 a year, pay $400 a month in other debts, have $40,000 down, and the rate is 6.5% over 30 years with 1.5% per year for tax, insurance and HOA.
- Gross monthly income = 80,000 ÷ 12 = 6,666.67
- Front-end cap = 0.28 × 6,666.67 = 1,866.67
- Back-end cap = 0.36 × 6,666.67 − 400 = 2,400 − 400 = 2,000
- Max housing payment = lesser of 1,866.67 and 2,000 = 1,866.67
- r = 6.5 ÷ 12 ÷ 100 = 0.00541667, n = 360, (1+r)ⁿ = 6.991798, so f = 0.00632068
- Monthly tax/insurance rate = 1.5 ÷ 100 ÷ 12 = 0.00125 per dollar of price
- Price = (1,866.67 + 0.00632068 × 40,000) ÷ (0.00632068 + 0.00125) = 2,119.50 ÷ 0.00757068
- Price ≈ 279,961, loan = 279,961 − 40,000 = 239,961
Result: Affordable home price ≈ $279,961, payment ≈ $1,867/mo, loan ≈ $239,961
You earn $120,000 a year, pay $800 a month in other debts, have $60,000 down, same 6.5% over 30 years and 1.5% for tax and insurance.
- Gross monthly income = 120,000 ÷ 12 = 10,000
- Front-end cap = 0.28 × 10,000 = 2,800
- Back-end cap = 0.36 × 10,000 − 800 = 3,600 − 800 = 2,800
- Max housing payment = lesser of 2,800 and 2,800 = 2,800
- Using f = 0.00632068 and tax/insurance rate 0.00125
- Price = (2,800 + 0.00632068 × 60,000) ÷ 0.00757068 = 3,179.24 ÷ 0.00757068
- Price ≈ 419,941, loan = 419,941 − 60,000 = 359,941
Result: Affordable home price ≈ $419,941, payment ≈ $2,800/mo, loan ≈ $359,941
Maximum monthly housing payment under the 28% front-end rule, by gross annual income
| Gross annual income | Gross monthly income | Max housing (28%) | Max total debt (36%) |
|---|---|---|---|
| $50,000 | $4,167 | $1,167 | $1,500 |
| $80,000 | $6,667 | $1,867 | $2,400 |
| $100,000 | $8,333 | $2,333 | $3,000 |
| $150,000 | $12,500 | $3,500 | $4,500 |
| $200,000 | $16,667 | $4,667 | $6,000 |
Roughly how much home you can afford at 6.5% over 30 years (assuming 20% down, no other debts, 1.5% tax and insurance)
| Gross annual income | Max housing payment | Approx. home price |
|---|---|---|
| $50,000 | $1,167 | ~$185,000 |
| $80,000 | $1,867 | ~$295,000 |
| $100,000 | $2,333 | ~$370,000 |
| $150,000 | $3,500 | ~$555,000 |
Common mistakes to avoid
- Using take-home pay instead of gross income. The 28/36 rule is based on gross income (before tax and deductions), the same figure lenders use. Plugging in your net pay will understate how much you can afford, sometimes by a wide margin.
- Forgetting taxes, insurance and HOA. Your monthly housing cost is not just principal and interest. Property tax, home insurance, HOA dues and (with less than 20% down) mortgage insurance all count toward the 28% limit, so leaving them out makes the budget look bigger than it really is.
- Ignoring existing debts. Car loans, student loans and credit card minimums all feed the 36% back-end limit. A few hundred dollars of monthly debt can cut tens of thousands off the home price you qualify for.
- Treating the result as the maximum you should spend. The 28/36 rule marks a sustainable ceiling, not a target. Buying right at the limit leaves little room for maintenance, emergencies or saving, so many buyers deliberately aim below it.
Glossary
- Gross monthly income
- Your total income before tax and deductions, divided by 12. The 28/36 rule is measured against this figure.
- Front-end ratio (28%)
- The share of gross monthly income that goes to your total housing payment. The rule keeps it at or below 28%.
- Back-end ratio (36%)
- The share of gross monthly income that goes to all debt payments combined, including housing. The rule caps it at 36%.
- Principal and interest (P&I)
- The part of your mortgage payment that repays the loan and its interest, separate from tax, insurance and HOA.
- Down payment
- The cash you pay upfront toward the home price. It is added to the loan you can carry to give the total price you can afford.
- PMI
- Private mortgage insurance, an extra monthly cost lenders usually require when your down payment is below 20% of the price.
Frequently asked questions
How much house can I afford on my income?
Under the 28/36 rule, your monthly housing payment should stay at or below 28% of your gross monthly income, and all your debts combined at or below 36%. The calculator turns that payment into a loan amount and adds your down payment, so on an $80,000 income with $40,000 down at 6.5% you could afford roughly a $280,000 home.
What is the 28/36 rule?
It is a lending guideline: spend no more than 28% of your gross monthly income on housing (the front-end ratio) and no more than 36% on total debt including housing (the back-end ratio). Your affordable payment is whichever limit is lower, which is why existing debts can reduce how much house you qualify for.
Does my down payment change how much I can afford?
Yes. Your income sets the size of mortgage payment you can support, and the down payment is added on top of the loan that payment buys. So a larger down payment raises the total home price you can reach, dollar for dollar, and may also help you avoid mortgage insurance.
Should I include property taxes and insurance?
Yes. Lenders count property tax, home insurance, HOA dues and any mortgage insurance as part of your housing payment, all of which fall under the 28% limit. This calculator subtracts an estimate for them before working out the loan, so enter a realistic percentage for your area.
Is the 28/36 rule the maximum a lender will approve?
Not always. The rule is a conservative guideline for affordability, but some loan programs approve higher ratios, especially with strong credit, large reserves or compensating factors. Being approved for more does not mean it is wise to borrow it, the rule reflects what is comfortably sustainable.
How can I afford a more expensive home?
You can raise your affordable price by increasing your down payment, paying off other debts to free up the 36% back-end limit, improving your credit to secure a lower rate, or increasing your qualifying income. Lower interest rates also help, since more of each payment then goes toward principal.
Sources
- How much house can I afford? , U.S. Consumer Financial Protection Bureau
- Debt-to-Income Ratio (DTI) , Investopedia