CompoundInterestCalc
Free online tool · Real estate

Mortgage Affordability Calculator

How much house can you actually afford? Enter your household income, monthly debt payments and down payment, and this free calculator applies the classic 28/36 debt-to-income rule to show a realistic home-price range — not just what a lender might approve.

You'll see your maximum monthly housing budget, the loan you could carry, and a full breakdown of the payment. Adjust the rate, term and your comfort level to find a number you can truly live with. No account, no sign-up.

Your finances
$
$
$
%
30 years
▶ Costs & comfort level
36%
%
$
$
Home price you can afford
$0
Max loan
$0
Housing budget
$0
Est. payment
$0
Where your monthly income goes
That payment, broken down
How much you can afford at each rate
Max home price

Estimates are for illustration and education only — not a loan pre-approval. Lenders weigh credit, employment and other factors this tool doesn't include.

The math

How much house you can afford

Affordability works backwards from your income. Lenders cap the share of your gross monthly income that can go to housing and to total debt — those two limits set your maximum payment, which sets your maximum loan.

Max housing payment = Gross monthly income × Front-end ratio
The front-end (housing) ratio is commonly around 28%; the back-end ratio caps all debt payments near 36–43%.
Max loan = (Payment − tax − insurance) capitalised at your rate & term
Whatever's left of the payment after tax and insurance is what supports the loan itself.
Worked example. On $8,000 gross monthly income, a 28% housing ratio allows about $2,240 a month. Set aside ~$500 for tax and insurance and roughly $1,740 supports the mortgage. At 6.5% over 30 years that backs a loan near $275,000 — plus your down payment for the total price you can target.
See it in action

Affordability at different incomes

Three household profiles under the 28/36 rule. Load any one into the calculator and adjust from there.

Quick guide

How to use the affordability calculator

Four short steps. Every field updates the affordable price, allocation and rate chart instantly.

Step 1

Enter your income

Your total household income before tax. Lenders base debt-to-income ratios on gross, not take-home, pay.

Step 2

Add your monthly debts

Minimum payments on car loans, student loans and credit cards. These directly reduce how much you can borrow.

Step 3

Set your down payment

The cash you'll put in. A bigger down payment lifts the price you can afford and can remove PMI.

Step 4

Tune the rate and comfort level

Enter today's rate and adjust the max debt-to-income slider — lower for a safer budget, higher to stretch.

Good to understand

How affordability is calculated

Affordability isn't about the biggest loan a bank will approve — it's about a payment that leaves room for the rest of your life. This calculator uses the time-tested 28/36 rule, the same guideline most lenders start from.

The 28% front-end ratio

The first limit says your total monthly housing cost — principal, interest, property tax, insurance and any PMI or HOA — shouldn't exceed 28% of your gross monthly income. This keeps your home from crowding out everything else.

The 36% back-end ratio

The second limit says your housing cost plus all other debt payments shouldn't exceed 36% of gross income. So the more you owe on cars, cards and student loans, the less is left for a mortgage. The calculator takes whichever of the two limits is stricter — and tells you which one is binding.

Why the interest rate chart matters

Rates move, and they move your buying power a lot. The chart shows the maximum home price you could afford across a range of rates, with your current rate marked. A single percentage point can swing affordability by tens of thousands of dollars — useful context when deciding whether to lock a rate or wait.

Who it's for

This tool is for anyone starting a home search and wanting a grounded number before they fall in love with a listing. Pair it with the mortgage calculator to see the exact payment once you've picked a price.

Browse all our free calculators for saving, investing and retirement.

Quick answers

Affordability calculator FAQ

What is the 28/36 rule?
A common lending guideline: spend no more than 28% of your gross monthly income on housing, and no more than 36% on total debt including housing. This calculator uses both and applies whichever limit is stricter.
Should I use gross or net income?
Gross — your income before taxes and deductions. Debt-to-income ratios are always calculated on gross pay, which is why the resulting budget can feel generous. Consider using a lower max DTI for a more comfortable real-world number.
What counts as monthly debt?
The minimum required payments on car loans, student loans, personal loans and credit cards. Everyday spending like groceries, utilities and subscriptions is not counted in the ratio, though you should still budget for it.
Does a bigger down payment help?
Yes, in two ways: it directly adds to the price you can afford, and once you reach 20% down it removes PMI, freeing up more of your monthly budget for the loan itself.
Is this a mortgage pre-approval?
No. It's an educational estimate. Real approval depends on your credit score, employment history, assets and the lender's own rules. Use this to set expectations, then talk to a lender for an actual pre-approval.