DTI & Loan Affordability Calculator – Max Mortgage Estimate

Debt-to-income (DTI) ratio is the percentage of your gross monthly income that goes toward debt payments. Lenders use it — alongside credit score and assets — to decide how much they'll let you borrow, because it's a direct measure of how much room your budget has for a new payment.

This calculator applies the 28/36 rule (or a custom preset you choose) to your income, existing debts, and desired loan terms to estimate the maximum loan amount, purchase price, and monthly payment you could realistically qualify for.

02Front-end vs back-end DTI

Lenders actually check two separate ratios, and your borrowing power is capped by whichever one is more restrictive for your situation.

• Front-end DTI: your housing payment alone (principal, interest, taxes, insurance, HOA) divided by gross income — commonly capped around 28%
• Back-end DTI: all monthly debt payments combined, including the new housing payment, divided by gross income — commonly capped around 36%
• Some loan programs allow higher back-end limits (up to 43–50%) for borrowers with strong credit or extra reserves

03How to improve your DTI ratio

• Pay down or pay off high-payment debts like car loans or credit cards before applying
• Increase your down payment to reduce the loan amount and monthly payment
• Add verifiable income, such as a co-borrower or a documented side income
• Choose a longer loan term or shop for a lower interest rate to reduce the monthly payment

04DTI limits by mortgage type

Lenders don't apply one universal DTI cutoff for a mortgage; the maximum you can carry depends heavily on the loan program. These are typical ranges, your own limit still depends on credit score, cash reserves, and the lender's specific underwriting guidelines.

• Conventional loans: usually capped around 45% back-end DTI, sometimes up to 50% with strong credit and reserves
• FHA loans: more flexible, often approving back-end DTI up to 43-50%, and occasionally higher with compensating factors
• VA loans: no fixed DTI ceiling in VA guidelines, but most lenders use 41% as a soft benchmark before requesting extra documentation

05Example

With an $85,000 gross annual income and $500/month in existing debts, a standard 28/36 DTI limit caps the new housing payment at roughly $1,983/month (28% of income) and total debt at $2,550/month (36% of income). Since $500 is already committed, the real ceiling for the new payment is the lower of the two limits after subtracting existing debt.