House Affordability Calculator

Direct answer

Start with gross monthly income and recurring monthly debt. A lender-style scenario may cap housing with a front-end ratio and cap total debt with a back-end ratio. The calculator then subtracts property tax, homeowners insurance, HOA dues, mortgage insurance, and other included housing costs from the monthly housing allowance. The remaining principal-and-interest budget is converted into a loan amount with the fixed-payment formula, and the down payment is added to estimate a home price.

Run at least three scenarios: a conservative household budget, a middle planning case, and a higher lender-style ceiling. The best decision is rarely the largest displayed number.

Continue with the Compare qualification with a comfortable budget. Turn the ceiling into a household decision.

How to use the calculator

1. Enter stable gross annual household income. Do not include income a lender may not accept unless you are using the tool only for personal budgeting.
2. Add required monthly debts: minimum credit-card payments, auto and student loans, support obligations, and other recurring debt that belongs in your chosen scenario.
3. Enter the down payment as cash or a percentage, and keep closing cash separate.
4. Use the annual note interest rate from a lender quote or a clearly labeled scenario. A sitewide average is not a personal quote.
5. Enter the loan term and the actual property-tax, insurance, HOA, and mortgage-insurance estimates when known.
6. Choose a DTI preset only as a scenario. CFPB notes that products and lenders use different DTI limits.
7. Compare the modeled ceiling with a payment that leaves room for utilities, repairs, savings, childcare, transport, and other household priorities.

Continue with Compare qualification with a comfortable budget or Estimate cash to close for the next calculation.

Formula and calculation sequence

Gross monthly income = annual gross income / 12.

Front-end housing cap = gross monthly income × selected front-end ratio.

Back-end housing cap = gross monthly income × selected back-end ratio − included monthly debts.

Modeled housing allowance = the lower applicable cap. In payment mode, it is the user's entered all-in monthly housing budget.

Principal-and-interest budget = housing allowance − monthly tax − monthly insurance − HOA − mortgage insurance − other included housing costs.

For a fixed-rate fully amortizing loan:

M = L × r(1 + r)^n / ((1 + r)^n − 1)

where M is periodic principal and interest, L is loan principal, r is the periodic note rate, and n is the number of payments. To solve for loan amount:

L = M × ((1 + r)^n − 1) / (r(1 + r)^n)

If the down payment, property tax, insurance, HOA, or mortgage insurance is a percentage of price or balance, the variables depend on the unknown home price. The implementation should solve iteratively until the all-in payment and price converge, not add percentage costs after solving.

Worked example with a limiting constraint

Assume $120,000 gross annual income, $600 of other monthly debt, a 28% front-end scenario, a 36% back-end scenario, $600 monthly property tax, $150 insurance, $100 HOA, no mortgage insurance, 6.50% annual note rate, 30 years, and a $60,000 down payment.

• Gross monthly income: $10,000.
• Front-end cap: $10,000 × 0.28 = $2,800.
• Back-end cap after other debt: $10,000 × 0.36 − $600 = $3,000.
• Limiting cap: $2,800 (front-end).
• Principal-and-interest budget: $2,800 − $600 − $150 − $100 = $1,950.
• Approximate supported loan at 6.50% for 360 payments: $308,511.
• Approximate price after adding the fixed $60,000 down payment: $368,511.

This example assumes fixed dollar estimates. A price-linked tax rate or mortgage-insurance rate requires iteration and changes the result.

To compare this result with another relevant method, open the Amortization Calculator. Inspect payment allocation, balance, and payoff over time.

Qualification ceiling versus comfortable budget

DTI answers a narrow question about income and debt under defined rules. It does not know whether a household has expensive childcare, irregular self-employment income, major medical costs, aggressive savings goals, or an older property likely to need repairs. CFPB specifically distinguishes what a lender may offer from what fits comfortably within the rest of a household budget. Show both concepts and label them.

What belongs in the monthly payment

Principal and interest are only the loan portion. A realistic housing total can also include property taxes, homeowners insurance, mortgage insurance, HOA or co-op dues, and other required assessments. Utilities and maintenance are normally budget items outside the lender payment; show them separately rather than silently treating them as escrow.

Cash to close is a separate constraint

Affording a monthly payment does not prove that the buyer has enough closing cash. A planning estimate may include down payment, estimated closing costs, prepaid taxes or insurance, initial escrow funding, deposits already paid, credits, and adjustments. The lender's Loan Estimate is the better document for a specific transaction. Do not present down payment + generic percentage as an exact cash-to-close figure.

Before setting a target price, use the guide to separate closing costs from cash to close.

Sensitivity checks that make the result useful

Compare the result at the entered rate, plus and minus 0.5 percentage point; with the entered tax and insurance quotes; with a higher maintenance reserve; and with at least two down payments. A sensitivity table should identify what changed and hold every other input constant. Do not mix updated rates with old property-cost assumptions.

For a controlled stress test, compare the same budget across rate scenarios.

Common mistakes

• Treating 28/36 as a universal approval rule. It is a planning convention, while lender and product limits vary.
• Calling annual percentage rate (APR) the interest rate used in the payment formula. Use the note rate unless the tool explicitly models APR cash flows.
• Ignoring taxes, insurance, HOA, mortgage insurance, or maintenance.
• Counting the same debt in both the housing-cost field and other-debt field.
• Adding down payment without reserving money for closing and emergencies.
• Using a regional default as if it were a quote for a specific property.
• Assuming a preapproval amount is a recommended spending target.

Inputs, outputs and result meaning

Calculates estimated home-price ceiling, estimated loan amount, modeled all-in monthly housing cost, and monthly principal and interest from planning mode, gross annual household income, other monthly debt payments, and housing DTI assumption with visible method, validation, precision, and limitations.

Inputs

Planning mode

Use lender-style income ratios or start from your own all-in monthly housing budget. Available choices are Income and DTI and Monthly budget only.

Gross annual household income

Income before taxes and deductions. Supported units include US dollars ($). The supported range is 1 through 100,000,000.

Other monthly debt payments

Recurring debt included in the back-end DTI test. Supported units include US dollars ($). The supported range is 0 through 1,000,000.

Housing DTI assumption

Editable planning ratio, not a universal approval rule. Supported units include percent (%). The supported range is 1 through 80.

Total DTI assumption

Editable total-debt ratio used after other monthly debts. Supported units include percent (%). The supported range is 1 through 80.

Comfortable all-in housing budget

Optional household ceiling. Enter 0 to use only the DTI ceiling. Supported units include US dollars ($). The supported range is 0 through 1,000,000.

All-in monthly housing budget

Amount available for principal, interest, taxes, insurance, HOA, and mortgage insurance. Supported units include US dollars ($). The supported range is 1 through 1,000,000.

Down payment entry

Choose how to express the down payment. Available choices are Fixed dollar amount and Percentage of price.

Down payment

Cash allocated to the purchase price. Supported units include US dollars ($). The supported range is 0 through 100,000,000.

Down payment percentage

Percentage of the modeled purchase price. Supported units include percent (%). The supported range is 0 through 99.

Annual interest rate (note rate)

Use the note rate, not APR, for principal-and-interest calculations. Supported units include percent (%). The supported range is 0 through 25.

Loan term

Length of the fixed-rate amortization schedule. Supported units include years (yr). The supported range is 1 through 50.

Property tax entry

Use a property-specific estimate where possible. Available choices are Annual dollar estimate and Annual percentage of price.

Annual property tax

Editable annual estimate. Supported units include US dollars ($). The supported range is 0 through 1,000,000.

Annual property tax rate

Percentage of the modeled home price. Supported units include percent (%). The supported range is 0 through 10.

Annual homeowners insurance

Annual policy estimate. Supported units include US dollars ($). The supported range is 0 through 1,000,000.

Monthly HOA or co-op dues

Monthly dues and required assessments included in housing cost. Supported units include US dollars ($). The supported range is 0 through 100,000.

Annual mortgage insurance rate

Annual percentage of the modeled loan balance; enter 0 when not applicable. Supported units include percent (%). The supported range is 0 through 10.

Other included monthly housing costs

Required housing costs included in the modeled payment. Supported units include US dollars ($). The supported range is 0 through 100,000.

Estimated closing costs

Planning percentage only; a lender Loan Estimate controls for a real transaction. Supported units include percent (%). The supported range is 0 through 20.

Prepaids and initial escrow funding

Estimated prepaid taxes, insurance, escrow funding, and deposits. Supported units include US dollars ($). The supported range is 0 through 1,000,000.

Credits and deposits already paid

Estimated credits that reduce cash due at closing. Supported units include US dollars ($). The supported range is 0 through 1,000,000.

Outputs

Estimated home-price ceiling

This is the primary result. The visible value uses up to 2 decimal places according to the output rule.

Estimated loan amount

The visible value uses up to 2 decimal places according to the output rule.

Modeled all-in monthly housing cost

The visible value uses up to 2 decimal places according to the output rule.

Monthly principal and interest

The visible value uses up to 2 decimal places according to the output rule.

Estimated cash to close

The visible value uses up to 2 decimal places according to the output rule.

DTI-based monthly ceiling

The visible value uses up to 2 decimal places according to the output rule. It appears only when the selected mode supports this result.

Price at rate minus 0.5 point

The visible value uses up to 2 decimal places according to the output rule.

Price at rate plus 0.5 point

The visible value uses up to 2 decimal places according to the output rule.

Lower applicable housing cap → subtract non-loan costs → solve fixed-rate loan and price. Keep the result label, unit, selected mode, and stated limitations together when sharing the answer.

Frequently asked questions

Primary sources

• CFPB — Affording a home: https://www.consumerfinance.gov/ask-cfpb/how-can-i-figure-out-if-i-can-afford-to-buy-a-home-and-take-out-a-mortgage-en-118/
• CFPB — Debt-to-income ratio: https://www.consumerfinance.gov/ask-cfpb/what-is-a-debt-to-income-ratio-en-1791/
• CFPB — Loan Estimate explainer: https://www.consumerfinance.gov/owning-a-home/loan-estimate/
• CFPB — Principal and interest versus total monthly payment: https://www.consumerfinance.gov/ask-cfpb/on-a-mortgage-whats-the-difference-between-my-principal-and-interest-payment-and-my-total-monthly-payment-en-1941/
• Fannie Mae — Mortgage Affordability Calculator: https://yourhome.fanniemae.com/calculators-tools/mortgage-affordability-calculator

Source research refreshed September 21, 2026. CalculatorGeek is not a lender, broker, financial planner, tax adviser, or legal adviser.