The house affordability calculator above answers the question every home shopper asks before they ever call a real estate agent: how much house can I actually afford? Instead of guessing or relying on what a lender's pre-approval letter says, this tool uses the same 28/36 rule that mortgage underwriters lean on every day, so the number you see reflects a payment you can realistically carry alongside the rest of your life.
Arb Digital built this calculator as part of a growing library of free financial tools because we believe people shopping for a home deserve clear numbers before they fall in love with a listing. Plug in your income, your existing debts, your savings, and the loan terms you're expecting, and you'll get an affordable price range in seconds β no email required, no login, no catch.
What This House Affordability Calculator Does
This calculator estimates the maximum home price you can comfortably purchase given your income, monthly debt obligations, available down payment, and the loan terms you enter. It applies the two-part 28/36 guideline that most conventional and FHA lenders still use as a sanity check during underwriting. The first number, 28%, caps your housing payment β principal, interest, taxes, and insurance, often shortened to PITI β at 28% of your gross monthly income. The second number, 36%, caps your total debt load, including that housing payment plus every other monthly obligation, at 36% of gross monthly income. The calculator runs both tests and uses whichever produces the lower affordable payment, then works backward through the mortgage math to translate that payment into a home price.
Because property taxes and insurance both scale with the price of the home itself, the math isn't a simple one-line formula β it has to solve for a price where the total monthly cost, taxes and insurance included, still lands under your budget. The calculator handles that algebra instantly so you don't have to.
How to Use It
- Enter your annual gross income. Use the combined pre-tax income of everyone who will be on the mortgage application.
- Add your total monthly debts. Include car payments, student loans, minimum credit card payments, and any other recurring obligations β but not rent or utilities.
- Enter your down payment. This is the cash you've saved and are willing to put down at closing.
- Set the interest rate and loan term. If you're not sure of the current rate, check a recent rate survey or ask a loan officer for a ballpark figure.
- Fill in property tax rate and insurance estimate. These vary a lot by state and county, so adjust them to match your target area if you can.
- Click Calculate to see your affordable home price, the maximum monthly payment behind it, and the loan amount that supports it.
The Formula Behind the 28/36 Rule
The calculator first figures your monthly gross income by dividing annual income by 12. It then computes two ceilings: 28% of that monthly income for housing costs alone, and 36% of monthly income minus your existing debts for total obligations. Whichever ceiling is lower becomes your maximum allowable monthly housing payment.
From there, the tool subtracts your estimated monthly insurance and works through the mortgage amortization formula to solve for the home price where principal and interest, plus property tax on that price, plus insurance, all add up to exactly your maximum payment. The down payment you enter reduces how much you need to borrow, so a larger down payment translates directly into a higher affordable price for the same monthly budget. This approach mirrors guidance published by the Consumer Financial Protection Bureau, the federal agency that oversees mortgage lending disclosures and homebuyer education.
Front-End vs. Back-End Ratios, Explained Simply
Lenders talk about two different debt-to-income ratios, and understanding the difference makes the 28/36 rule click. The front-end ratio only counts your housing payment against your income β that's the 28% side. The back-end ratio counts every debt you carry, housing included, against your income β that's the 36% side. Most of the time the back-end ratio is the binding constraint, especially for buyers who are still paying off a car loan or student debt, because those payments eat into the 36% ceiling before housing even enters the picture. That's exactly why paying down a credit card balance or finishing off a small loan before you shop for a house can unlock a meaningfully higher price range, sometimes more than saving another year for a down payment would.
Some loan programs, particularly FHA and certain conventional programs with strong compensating factors like excellent credit or large cash reserves, allow back-end ratios above 36%, occasionally as high as 43% to 50%. This calculator uses the traditional 28/36 benchmark because it represents a conservative, comfortable affordability line rather than the absolute maximum a lender might approve. Just because you qualify for more doesn't mean you should borrow more β a payment that maxes out what a lender allows can leave very little room for savings, repairs, or the unexpected.
How Your Down Payment Changes the Math
Every dollar you put down is a dollar you don't have to finance, which means it doesn't generate a monthly principal-and-interest payment. That has a multiplying effect on affordability: a $10,000 increase in your down payment doesn't just raise your home price by $10,000, it also frees up a small sliver of your monthly budget that would have gone toward interest on that portion of the loan, which the calculator then reallocates toward an even higher purchase price. This is why buyers who can scrape together 15% or 20% down instead of 5% or 10% often see a bigger jump in affordable price than the raw down payment increase would suggest. It's also why mortgage insurance, which typically kicks in below 20% down on conventional loans, matters β this calculator doesn't include PMI in the payment estimate, so if your down payment is under 20%, budget some extra room for it. Our PMI calculator can estimate that added monthly cost precisely.
Costs Lenders Factor Into Your Payment
A mortgage payment is rarely just principal and interest. Lenders bundle in property taxes and homeowners insurance, and often mortgage insurance too, into a single monthly PITI figure that gets weighed against your income. Property tax rates vary enormously by location β some counties charge under 0.5% of assessed value annually, while others charge well over 2%. Homeowners insurance premiums also swing based on your state, your home's construction, and local risk factors like flood or wildfire exposure. Because both of these costs scale with home price, they quietly shrink your affordable price more than most buyers expect, which is exactly why this calculator solves for them explicitly rather than ignoring them.
- Principal and interest β the core loan repayment
- Property taxes β set by your county or municipality
- Homeowners insurance β required by virtually every lender
- Mortgage insurance β often required below 20% down
- HOA dues β not included here, but worth checking separately if you're eyeing a condo or planned community
See how your loan amount stacks up against typical closing costs before you make an offer. Arb Digital also builds fast, high-converting websites and content for businesses β explore our other free tools while you plan.
Estimate Closing Costs All Free ToolsCommon Mistakes to Avoid
- Using net income instead of gross income. Lenders and this calculator both work from pre-tax income, not take-home pay.
- Forgetting a debt payment. Leaving out a car loan or a co-signed student loan will inflate your affordable price beyond what a lender will actually approve.
- Ignoring property tax differences by location. A 0.6% tax rate and a 2% tax rate on the same home price produce very different monthly payments.
- Assuming the maximum price is the target price. The 28/36 rule marks a ceiling, not a recommendation β many buyers are more comfortable at 80-90% of the calculated maximum.
- Skipping PMI when putting down less than 20%. Add that cost separately so your monthly budget stays accurate.
Related Free Tools From Arb Digital
Once you know your target price range, dig deeper with the closing cost calculator to estimate cash needed at signing, the mortgage DTI calculator to double-check your debt-to-income ratios, the mortgage prequalification calculator to see an estimated loan amount, and the mortgage calculator to model different rates and terms side by side. You can also browse our free online tools hub for the full library.
Frequently Asked Questions
Using the 28/36 rule with typical debts and a moderate down payment, many buyers earning $90,000 a year land in the $300,000 to $400,000 range, though your exact number depends heavily on your debts, down payment, and local tax rates. Run your own numbers through the calculator above for a precise figure.
It's a guideline stating your housing payment shouldn't exceed 28% of gross monthly income, and your total debt payments, housing included, shouldn't exceed 36% of gross monthly income. Many lenders still reference it even though some loan programs allow higher ratios.
Yes. It solves for a home price where principal, interest, estimated property taxes, and estimated homeowners insurance together stay within your maximum monthly payment.
Because the 36% back-end ratio caps total debt, not just housing. Every dollar of monthly debt payment you eliminate frees up a dollar of room the calculator can allocate toward a housing payment instead.
Not necessarily. Lenders may approve more or less depending on your credit score, loan program, reserves, and other compensating factors. This tool gives a conservative, educational estimate based on a widely used industry guideline.
Not always. The calculated figure is a ceiling based on income and debt alone β it doesn't account for savings goals, future expenses, or your personal comfort with risk, so many buyers choose to stay comfortably below it.
This tool provides general estimates for educational purposes only and is not financial, tax, legal, or medical advice. Figures are illustrative; consult a licensed professional for decisions.
