Mortgage Affordability Calculator
Work out how much house you can afford using the same debt-to-income rule lenders apply. Enter your income, existing debts and deposit to see your maximum purchase price, loan size and monthly housing budget — under conventional, FHA or VA standards.
Your finances
Use the total household income before tax — lenders count all borrowers.
Car loans, student loans, minimum card payments and child support.
20% avoids private mortgage insurance on a conventional loan.
The APR quoted on a 30-year fixed conventional loan.
Escrowed costs count toward the housing ratio but do not repay principal.
CFPB Ability-to-Repay guideline; Fannie Mae/Freddie Mac 28/36 rule
- Maximum home price
- $420,720.67
- Maximum loan
- $360,720.67
- Housing budget
- $2,800.00
- Back-end DTI
- 34.5%
14% down payment of $60,000.00
Over 30 yrs at 6.50%
Set by the front-end ratio (Conventional (28/36))
Limit 36% under Conventional (28/36)
How your monthly income is allocated
Housing, escrow and existing debts at the maximum affordable price.
- Principal & interest
- Tax, insurance & HOA
- Other monthly debts
- Remaining income
| Category | Value |
|---|---|
| Principal & interest | $2,280.00 |
| Tax, insurance & HOA | $520.00 |
| Other monthly debts | $650.00 |
| Remaining income | $6,550.00 |
Debt-to-income ratios
Front-end 28.0% · back-end 34.5% against the Conventional (28/36) limits.
| Category | Value |
|---|---|
| Current | 34.5% |
| Maximum | 60.0% |
Income required at each home price
Gross annual income needed to stay within the 28% front-end ratio.
- $250,000.00
- $400,000.00
- $550,000.00
- $700,000.00
- $850,000.00
| Category | Value |
|---|---|
| $250,000.00 | $73,754.11 |
| $400,000.00 | $114,387.05 |
| $550,000.00 | $155,020.00 |
| $700,000.00 | $195,652.94 |
| $850,000.00 | $236,285.89 |
Loan balance vs equity on the maximum purchase
Principal falls while your equity in the home rises.
- Loan balance
- Home equity
| Category | Value |
|---|---|
| Y1 | Loan balance: $360,394.57 · Home equity: $60,326.10 |
| Y2 | Loan balance: $355,285.71 · Home equity: $65,434.96 |
| Y3 | Loan balance: $349,745.63 · Home equity: $70,975.04 |
| Y4 | Loan balance: $343,737.97 · Home equity: $76,982.70 |
| Y6 | Loan balance: $337,223.22 · Home equity: $83,497.45 |
| Y7 | Loan balance: $330,158.59 · Home equity: $90,562.08 |
| Y8 | Loan balance: $322,497.69 · Home equity: $98,222.98 |
| Y9 | Loan balance: $314,190.18 · Home equity: $106,530.49 |
| Y11 | Loan balance: $305,181.46 · Home equity: $115,539.21 |
| Y12 | Loan balance: $295,412.38 · Home equity: $125,308.29 |
| Y13 | Loan balance: $284,818.75 · Home equity: $135,901.92 |
| Y14 | Loan balance: $273,330.95 · Home equity: $147,389.72 |
| Y16 | Loan balance: $260,873.55 · Home equity: $159,847.12 |
| Y17 | Loan balance: $247,364.69 · Home equity: $173,355.98 |
| Y18 | Loan balance: $232,715.63 · Home equity: $188,005.04 |
| Y19 | Loan balance: $216,830.12 · Home equity: $203,890.55 |
| Y21 | Loan balance: $199,603.81 · Home equity: $221,116.86 |
| Y22 | Loan balance: $180,923.52 · Home equity: $239,797.15 |
| Y23 | Loan balance: $160,666.54 · Home equity: $260,054.13 |
| Y24 | Loan balance: $138,699.80 · Home equity: $282,020.87 |
| Y26 | Loan balance: $114,878.97 · Home equity: $305,841.70 |
| Y27 | Loan balance: $89,047.55 · Home equity: $331,673.12 |
| Y28 | Loan balance: $61,035.83 · Home equity: $359,684.84 |
| Y29 | Loan balance: $30,659.82 · Home equity: $390,060.85 |
- Gross monthly income
- $10,000.00
- Front-end cap (28%)
- $2,800.00
- Back-end cap (36%)
- $2,950.00
- Binding housing budget
- $2,800.00
- Principal & interest
- $2,280.00
- Maximum loan amount
- $360,720.67
- Maximum home price
- $420,720.67
- Down payment share
- 14.3%
The front-end ratio is doing the limiting
Your front-end ratio is 28.0% and your back-end ratio is 34.5%. Under the Conventional (28/36) standard the front-end ratio caps the housing budget at $2,800.00 a month. Paying down $650.00 of other debt would raise the back-end cap and could unlock a larger loan.
Amortization schedule
360 payments · 360 rows
Amortization schedule
360 payments · 360 rows
This calculator is provided for general information only and is not financial advice or a lending commitment. Lenders also weigh credit score, employment history, reserves and the property appraisal, so the maximum price shown here is an estimate. DTI limits vary by programme and by lender overlay.
How mortgage affordability is calculated
Lenders do not start with the price of the house. They start with your income, subtract the debts you already carry, and work backwards to the largest monthly payment you can sustain. That payment is then converted into a loan amount using the standard amortising payment formula, and your deposit is added on top to give the maximum purchase price.
Step 1 — Apply the front-end and back-end caps
The front-end ratio limits housing costs as a share of gross monthly income. The back-end ratio limits housing plus all other debt. The lower of the two caps is the one that binds.
frontEndCap = grossMonthlyIncome × frontEndDTI
backEndCap = grossMonthlyIncome × backEndDTI − monthlyDebts
housingBudget = min(frontEndCap, backEndCap)Step 2 — Strip out escrow to find the loan payment
Property tax, homeowners insurance, private mortgage insurance and HOA dues are part of the housing payment but they do not repay principal. Subtract them from the housing budget to find the amount available for principal and interest.
availableForLoan = housingBudget − monthlyEscrowStep 3 — Invert the amortising payment formula
The Reg. Z Appendix J payment formula is rearranged to solve for the present value — the loan amount that a given payment can service.
M = P × [ i(1 + i)^n ] ÷ [ (1 + i)^n − 1 ]
P = M × [ (1 + i)^n − 1 ] ÷ [ i(1 + i)^n ]
where i = annualRate ÷ 12 and n = term in monthsStep 4 — Add the down payment
maxHomePrice = maxLoanAmount + downPaymentWorked example — a $120,000 US household
Take a gross salary of $120,000, which is $10,000 a month. Existing car and card payments total $650 a month, the deposit is $60,000, the rate is 6.5% over 30 years and escrow is $520 a month.
- Front-end cap: $10,000 × 28% = $2,800
- Back-end cap: $10,000 × 36% − $650 = $2,950
- Binding housing budget: $2,800 (front-end)
- Available for principal and interest: $2,800 − $520 = $2,280
- Maximum loan at 6.5% over 360 months: $360,721
- Maximum purchase price: $360,721 + $60,000 = $420,721
The resulting ratios are 28.0% front-end and 34.5% back-end, both inside the conventional limits. Notice that the front-end cap binds here — the $650 of other debt is not large enough to trigger the back-end constraint.
Worked example — when the back-end ratio binds
Now raise the other monthly debt to $1,400. The back-end cap becomes $10,000 × 36% − $1,400 = $2,200, which is below the $2,800 front-end cap. The housing budget falls to $2,200, leaving $1,680 for principal and interest, which supports a loan of about $265,794 and a purchase price of roughly $325,794. Clearing $750 of that debt would restore the full front-end budget — a far bigger gain than shopping for a lower rate.
Worked example — a UK borrower
A UK household earning £75,000 with a £25,000 deposit, no unsecured debt and a 5.0% rate over 25 years would typically be assessed on an income multiple of about 4.5×, giving a maximum loan near £337,500 and a purchase price near £362,500. UK lenders must also stress-test affordability under FCA MCOB 11, so the figure a lender will actually offer is often lower than a simple multiple suggests.
How to use this calculator
- Enter your gross annual household income before tax, including every borrower on the application.
- Add your other monthly debt payments — car loans, student loans, minimum card payments and child support.
- Set your down payment. Aim for 20% to avoid private mortgage insurance on a conventional loan.
- Choose a rate and term. A 30-year term lowers the payment and raises the affordable price; a 15-year term does the opposite.
- Enter the monthly escrow for property tax, insurance and HOA dues.
- Pick a lending standard — conventional 28/36, FHA 31/43, VA 41/56 or a conservative 25/33 buffer.
- Read the maximum home price and check which ratio is binding. Paying down debt or saving more deposit moves the number fastest.
What this calculator does not include
Lenders also weigh credit score, employment history, cash reserves, the property appraisal and any lender-specific overlays. A high credit score can push the approved DTI above the guideline, while a thin credit file can pull it below. Treat the maximum price shown here as a well-founded starting point for a conversation with a mortgage adviser, not as a lending decision.
Frequently asked questions
Still unsure about something? Our contact page reaches a real person, usually within two business days.