Debt to Income Ratio Calculator for Mortgage
Your debt-to-income ratio divides total monthly debt payments by gross monthly income. Conventional lenders use the 28/36 guideline: housing costs should not exceed 28 percent of gross income, and all debts combined should stay at or below 36 percent. Enter your income and obligations in the calculator above to see both ratios and how they compare to lender thresholds.
Your loan
Taxes, insurance and extra payments
$0.00
on a $0 loan at 0% loan-to-value
- Principal & interest
- $0.00
- Property tax
- $0.00
- Home insurance
- $0.00
- PMI
- $0.00
- HOA dues
- $0.00
- Total monthly
- $0.00
Principal overtakes interest in month 0 (—), then most of every payment is yours.
- Total of payments
- $0
- Paid off
- —
- PMI cancellable
- month —
Estimates from the figures you entered, not a loan offer. Taxes and insurance vary by property; your lender's escrow figure is the one that counts.
Front-End vs Back-End DTI
The front-end ratio — sometimes called the housing ratio — counts only housing-related costs: principal, interest, property taxes, homeowner's insurance, PMI, and HOA fees. The conventional ceiling is 28 percent of gross monthly income. On a $6,500 gross income, that limits housing costs to $1,820.
The back-end ratio adds every other recurring monthly obligation: car loans, student loans, minimum credit-card payments, personal loans, child support, and alimony. The conventional ceiling is 36 percent. On the same $6,500 income, total debts must stay at or below $2,340. If non-housing debts already consume $700 per month, only $1,640 remains for housing under the back-end rule — less than the $1,820 front-end cap.
Lenders evaluate both ratios and typically use whichever is more restrictive. In practice, the back-end ratio is the binding constraint for most borrowers because existing debts eat into the housing budget. The calculator highlights which ratio is limiting your approval so you know where to focus.
DTI Thresholds by Loan Type
The 28/36 rule applies to conventional conforming loans sold to Fannie Mae or Freddie Mac. These are the most common residential mortgages and the thresholds most borrowers encounter.
FHA-insured loans use a more generous pair: 31 percent front-end and 43 percent back-end. Compensating factors — such as significant cash reserves, minimal payment shock, or residual income above a threshold — can allow approval at the upper end. Without those factors, underwriters tend to stay closer to the standard numbers.
The Qualified Mortgage rule, enforced by the CFPB, imposes a hard cap at 43 percent total DTI for most lenders regardless of loan programme. Loans that exceed 43 percent do not qualify for the legal safe harbour that QM status provides, making lenders reluctant to approve them.
If your ratio is too high, the most direct lever is reducing existing debt before applying. Even paying off a single obligation can shift the ratio by several points. The affordability calculator with debts lets you model the impact of eliminating a specific payment on your maximum purchase price.
DTI thresholds are guidelines, not guarantees of approval. Individual lenders may apply stricter overlays based on their risk appetite.
Year-by-year amortization schedule
| Year | Principal paid | Interest paid | Balance |
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