Home Affordability Calculator: How Much House Can I Afford?

Home affordability depends on both monthly payment room and cash available upfront. Income and existing debts shape the housing budget, while the down payment, mortgage rate, taxes, insurance and other property costs determine how much home that budget can support.

How to Use the Home Affordability Calculator

Start with annual gross income, recurring non-housing debt payments and cash available specifically for the down payment. Leave the debt field blank when no counted monthly debts apply.

Next, enter the mortgage term and note rate, plus estimated property taxes, homeowners insurance, mortgage insurance and HOA dues. Mortgage insurance and HOA can be left blank when they do not apply.

Use the 28% housing and 36% total-DTI values as editable planning assumptions. They are common rule-of-thumb starting points rather than mortgage-program approval limits.

What the Main Results Mean

Estimated max home price is the highest modeled purchase price that fits the selected DTI assumptions, down-payment cash and entered property costs.

Monthly housing cost combines principal and interest with property taxes, homeowners insurance, mortgage insurance and HOA dues.

Review metrics highlight the monthly housing budget created by the tighter DTI constraint, non-principal-and-interest housing costs and which DTI assumption is actually limiting the modeled price.

How the Calculator Solves for Home Price

Annual gross income is converted to monthly income first:

One monthly limit comes from the housing assumption. Another comes from the total-DTI assumption after non-housing debts are subtracted.

Whichever amount is lower becomes the modeled housing budget. Price is then solved upward until principal, interest, taxes, insurance, mortgage insurance and HOA costs reach that budget.

Why 28/36 Is a Starting Point, Not an Approval Rule

The 28/36 rule remains a widely used home-affordability reference, and major consumer mortgage calculators still use it as a baseline. Actual underwriting can apply different total-DTI limits depending on the loan program, underwriting method and full borrower profile.

Current Fannie Mae guidance, for example, distinguishes manually underwritten loans from Desktop Underwriter rather than using one universal total-DTI maximum. Planning calculators should therefore let users edit the assumptions instead of presenting 28% and 36% as qualification promises.

Reducing the ratios creates a more conservative price estimate. Raising them shows a more leveraged scenario, not an assurance that a lender will approve the result.

The DTI calculator can be used when the ratio itself needs to be examined separately.

Include the Full Monthly Housing Cost

Principal and interest are only part of the monthly cost of owning a home. Property taxes, homeowners insurance, mortgage insurance when required and HOA dues can materially reduce the price supported by the same housing budget.

Current homebuying guidance treats the total monthly home payment as more than principal and interest and recommends budgeting for taxes, insurance and other ownership costs.

Mortgage insurance is kept as a user-supplied monthly estimate. Borrowers with less than 20% down commonly need mortgage insurance on conventional financing, while FHA and USDA structures use their own insurance rules.

Once a purchase price is known, the task changes from affordability to payment estimation. The mortgage calculator is better suited to that scenario.

Down Payment Cash Is a Real Constraint

Using a fixed cash amount is useful when solving backward for home price because available cash does not automatically rise with the calculated purchase price.

Results show both the dollars used and the resulting down-payment percentage. More cash reduces the amount financed and can support a higher price at the same monthly budget.

Closing costs, prepaid taxes and insurance, moving costs and reserves remain separate. Buyers should account for those expenses and savings priorities rather than using every available dollar to buy a larger home.

Interest Rate, Property Costs and Debt Can Move the Result Quickly

Higher mortgage rates raise principal and interest for the same loan amount, which reduces the home price supported by a fixed monthly budget. Use the mortgage note rate rather than APR in the payment formula.

Property taxes, insurance, mortgage insurance or HOA dues have the same directional effect when they rise because more of the budget is consumed before principal and interest.

Tighter housing DTI assumptions can make debt reduction irrelevant to the maximum price until total DTI becomes the binding constraint. Once total DTI is tighter, lower recurring debts can expand housing room.

Affordability Is Broader Than Mortgage Qualification

DTI-based maximums are not automatically the amount a household should spend. Mortgage qualification and household affordability answer different questions.

Maintenance, repairs, utilities, furnishings, moving costs and emergency savings are outside the formal DTI calculation. Buyers may also face changing insurance or property-tax costs after purchase.

Use the maximum as a scenario boundary, then test a lower target, higher property costs or less down-payment cash. Prices that still work under less favorable assumptions leave more room for the rest of the household budget.