Should I use gross or net income to calculate home affordability?

Use gross income, which is the amount you earn before taxes and deductions. Mortgage lenders and the 28/36 rule are both based on gross income, so using net income will understate the price you can actually qualify for.

Do credit card balances count as debt when calculating home affordability?

Yes. Lenders use the minimum monthly payment on every credit card you carry a balance on, not the full balance. Paying cards down to zero before applying removes that minimum payment and raises the price you can afford.

How does the down payment change the home I can afford?

A larger down payment reduces the loan you need to take out, which lowers the monthly payment for the same home or lets you buy a more expensive home at the same monthly cost. The Home Affordability Calculator updates the maximum price as soon as you change the down payment field.

Does a longer loan term always make a home more affordable?

It raises the affordable price by lowering each monthly payment, but it also increases the total interest paid over the life of the loan. A longer term is useful for qualifying power, while a shorter term saves money if you can afford the higher payment.

How often should I recalculate my home affordability?

Recalculate whenever a major input changes: a raise, a new debt, a payoff, a change in down payment savings, or a meaningful move in interest rates. Even small changes in any of these can shift the affordable price by thousands of dollars.

What is the fastest way to raise the home price I can afford?

Pay down existing recurring debts so more of the 36% back-end cap is freed up for housing. A larger down payment comes next, followed by securing a lower interest rate or extending the loan term. Raising stable gross income has the largest effect but is usually the slowest lever to move.

Is the 28/36 rule a hard approval limit?

No. It is a planning guideline that closely matches the test most underwriters run during prequalification. Some loan programs and compensating factors can push approvals above 36% back-end, but staying inside the rule usually leaves a safer cushion for rate changes and unexpected expenses.

How to Calculate Home Affordability With the 28/36 Rule

Q: What is the 28/36 rule for home affordability?

The 28/36 rule says your total monthly housing payment should stay at or below 28% of your gross monthly income, and your total monthly debt payments including housing should stay at or below 36% of gross monthly income.

Q: Are property taxes and homeowners insurance included in the 28% housing cap?

Yes. The 28% front-end ratio is meant to cover the full monthly cost of owning the home, including principal, interest, property taxes, homeowners insurance, private mortgage insurance when required, and homeowners association dues where applicable.

To calculate home affordability, lenders apply the 28/36 rule: your total monthly housing payment should not exceed 28% of your gross monthly income, and your total monthly debt payments including housing should stay at or below 36% of gross monthly income. Gross income means earnings before any taxes or deductions are taken out. From that figure, the lender subtracts the recurring debts you already owe, such as car loans, student loans, and credit-card minimums, then determines how large a mortgage payment you can carry. Combined with your down payment and the interest rate you can expect, that monthly payment is then turned into a maximum loan amount and, in turn, a maximum home purchase price. The result is the realistic ceiling on what you can afford right now, not a stretched approval that leaves you house-poor.

The 28/36 framework is the same test most mortgage underwriters apply during prequalification, which is why a quick estimate at home tracks closely with what a bank will later confirm. The two thresholds work together: the 28% front-end ratio protects you from spending too much on shelter alone, while the 36% back-end ratio keeps every required monthly payment in check. Falling outside either one signals that a stretch today becomes a strain if rates rise or income dips, so the rule is built for resilience as much as qualification.

Borrowers often confuse the two ratios because both are stated as a percentage of the same income number, but the front-end ratio and the back-end ratio answer different questions. The 28% figure answers, "How much can shelter alone cost me each month?" The 36% figure answers, "How much can every required payment combined cost me each month, including shelter?" Lenders run both tests and keep the more restrictive answer. A household with low existing debts will usually be limited by the 28% ceiling, while a household with a car loan or sizable student loan balance will often be limited by the 36% ceiling even though its 28% headroom looks generous on paper.

What Inputs Determine How Much House You Can Afford

Five numbers drive the answer, and each one pulls the result in a specific direction. Knowing the role of every input helps you decide which lever to move first.

Gross monthly income. Every affordability figure is a percentage of this number, so a raise, a bonus, or a second earner in the household moves the ceiling up sharply. Switching the income from monthly to annual does not change the result, only how the value is entered.
Recurring monthly debts. Car payments, student loans, credit-card minimums, child support, and any other installment loans count toward the 36% back-end limit. The higher these debts are, the less room you have for housing, and the smaller the home you can afford.
Down payment. Cash you bring to the closing reduces the loan you need. Because the loan drives the monthly payment, a larger down payment lets you buy a more expensive home at the same monthly cost, or the same home at a lower monthly cost.
Interest rate. A higher rate means a larger share of each payment goes to interest, which shrinks the loan you can support at any given payment. Even a small change in rate produces a noticeable swing in the affordable price.
Loan term. A longer term spreads the balance across more months and lowers each payment, which raises the loan you can carry. A shorter term does the opposite, but it also builds equity faster and costs less total interest.

If you only want to see the monthly payment that comes with a specific loan amount, the Mortgage Calculator shows that figure directly. Home affordability is the reverse question, starting from your budget and solving for the home price.

How the 28/36 Rule Translates Into a Maximum Home Price

The rule is applied in two stages, and each stage answers a different question. Understanding both stages makes it easier to interpret the numbers a calculator returns.

Stage 1: Front-End Ratio (28%)

The lender multiplies your gross monthly income by 0.28 to set the maximum amount you can spend on housing each month. That ceiling covers principal, interest, property taxes, homeowner's insurance, and, when applicable, private mortgage insurance and homeowners association dues. The result is your housing budget, separate from any other debt.

Stage 2: Back-End Ratio (36%)

The lender multiplies gross monthly income by 0.36 to set the cap on every required monthly payment combined. Subtracting your existing recurring debts from that cap leaves the room available for housing. If this back-end room is smaller than the 28% figure, the back-end number governs and your real housing budget is the lower of the two.

Stage 3: From Payment to Price

The housing budget becomes a loan amount using the expected interest rate and term, then the down payment is added back to reach the maximum home price. Because the loan calculation depends on rate and term, the same income and debts can support different price points under different loan structures.

Run the Numbers With the Home Affordability Calculator

The fastest way to get a complete picture is to enter your real numbers into the Home Affordability Calculator, which applies the 28/36 test automatically as you change any input. Use the steps below for the most accurate answer.

Enter your gross income in the income field and select whether the figure is monthly or annual. If you share the mortgage with a co-borrower, add both incomes together before entering.
Add up every recurring monthly debt you owe, including car loans, student loans, and credit-card minimum payments, and enter the total in the debts field. Skip utility bills, groceries, and discretionary spending; only required minimum payments count.
Enter the cash you plan to bring to closing as the down payment. Leave gift funds and equity from another sale out of this field for now; treat them as a separate adjustment once you have a baseline number.
Enter the interest rate you expect to qualify for and the loan term in years, typically 30 or 15. If you are unsure of the rate, use a current national average as a placeholder and rerun the calculation when you have a real quote.
Read the three outputs the calculator provides: the maximum home price you can afford, the loan amount that supports it, and the maximum monthly housing payment that the 28/36 rule allows. Change any input and all three numbers update instantly.

Once you have an affordable price, you can compare it against the monthly payment for the exact loan you would take out using the Mortgage Calculator to confirm both tools agree on the payment side of the equation.

What the Results Tell You

Three numbers come back, and each one serves a different planning purpose. The maximum home price is the headline figure for house hunting. The maximum monthly housing payment is the budget guardrail for ongoing affordability, including taxes and insurance. The affordable loan amount is the figure to compare against any specific listing once you subtract the down payment you intend to use.

If the affordable price feels low, the inputs almost always point to the cause. A quick way to read the result is to look at which of the two ratios binds. When the 28% front-end cap is the smaller number, your income is healthy relative to your debts, and a larger down payment or a longer term will move the ceiling the most. When the 36% back-end cap binds, your existing debts are the bottleneck, and paying those down produces the largest jump in the affordable price.

Common Scenarios and How the Answer Changes

The relationship between each input and the final price follows a predictable direction, even when the exact figures differ from one household to the next. The table below shows the qualitative effect of changing one input at a time, holding everything else constant. For your own numbers, plug them into the calculator.

Change Made	Direction of Affordable Price	Why It Moves
Higher gross income	Increases	Both the 28% and 36% caps scale with income
Higher recurring debts	Decreases	Less of the 36% cap is left for housing
Larger down payment	Increases	The required loan shrinks, so the same payment covers more home
Higher interest rate	Decreases	Each payment covers less principal, so the loan must shrink
Longer loan term	Increases	The balance is spread across more payments, lowering the monthly cost

For a deeper walk-through of how a down payment, rate, and term turn a payment into a price, the guide Determine Your Affordable Home Purchase Price in 3 Simple Steps lays out the math in plain language and pairs well with the calculator.

Where the 28/36 Rule Fits Among Other Tests

The 28/36 rule is the most widely cited guideline, but it is not the only one a borrower should know. Lenders running automated underwriting systems, such as the FICO-driven models used by many U.S. mortgage programs, often approve loans that exceed 36% back-end when compensating factors like excellent credit, large reserves, or a low loan-to-value ratio are present. Government-backed programs, including FHA loans, allow higher back-end ratios in some cases, while conventional conforming loans tend to stick closer to 36%. The 28/36 rule is best treated as a conservative planning anchor rather than a hard ceiling, because your lender may approve a slightly larger loan while your personal budget may want you to cap yourself lower.

A useful mental model is to think of the 28/36 rule as your planning baseline, the lender's automated approval as your upside ceiling, and your own comfort level as the final filter. Most financial planners recommend staying well inside the 28% front-end ratio once property taxes, insurance, maintenance, and HOA dues are included, because real-world ownership costs run higher than the headline mortgage payment alone.

Tips for Getting a Realistic Result

The 28/36 rule gives a lender's view of what you can borrow. Your personal comfort zone may sit lower, and a few habits make the estimate more honest.

Use gross income from all stable sources, but skip one-time bonuses you cannot count on in a slow year.
Include every minimum monthly payment, even small credit-card balances, because underwriters include them too.
Add a property-tax and insurance estimate to the housing payment so the 28% cap reflects real cost, not just principal and interest.
Stress-test the result by raising the interest rate by one or two points and rerunning the calculation; if the affordable price collapses, you have less cushion than the headline number suggests.
Recheck the figures whenever a major input changes, such as a new car loan, a raise, or a payoff of an existing debt.

For broader planning, the Savings Calculator can show how an extra down payment saved over one to three years shifts the affordable price, and the guide on mortgage payments walks through the payment side of the same numbers.

Frequently Rechecked Numbers

Three inputs are worth revisiting before you make an offer: the interest rate you can actually qualify for, the property-tax rate in the area you are targeting, and the size of your recurring debts. The first two can move your affordable price by tens of thousands of dollars, and the third shifts it in real time as you pay off car loans, student loans, or credit-card balances. A figure that looked tight six months ago can become comfortable after a single debt is cleared, which is one reason the 28/36 rule rewards steady debt reduction long before you start touring homes.

Putting It All Together

Start with honest inputs: gross income, every recurring monthly debt, the down payment you can actually commit, a realistic interest rate, and a loan term you can live with. Run those through the Home Affordability Calculator to read off the maximum home price, the loan amount, and the maximum monthly housing payment the 28/36 rule allows. Treat that price as a ceiling, not a target, and leave room in the monthly budget for repairs, maintenance, and the small surprises every homeowner eventually meets. If the ceiling sits below the homes you want, the most powerful levers are usually paying down existing debts, saving a larger down payment, or finding a way to raise stable income, all of which the calculator will reward the moment you re-enter the new numbers.