28 36 Rule Calculator - Housing Debt Check

The 28 36 rule calculator compares a proposed housing payment and other monthly debts with gross monthly income. It is useful before a home search, before a mortgage preapproval conversation, after a rate quote changes, or when a car loan or student loan payment shifts your monthly debt picture.

• • Preapproval planning: Check whether a target monthly payment sits inside a traditional mortgage screening range before you speak with lenders.
• • Offer budgeting: Translate a payment estimate into front-end and back-end ratios before deciding how aggressive an offer feels.
• • Debt payoff tradeoffs: See how reducing credit card, auto, or student loan payments can open more room for housing.
• • Rate-change review: Recheck the ratios when interest rates, taxes, insurance, or HOA dues move the estimated payment.

The rule has two parts. The first number looks only at housing expense compared with gross monthly income. The second number looks at housing plus recurring debt payments compared with the same income. The stricter part controls the result, so a household can pass the housing side and still be limited by auto loans, credit cards, student loans, or other recurring debts.

Use the output as a planning screen, not as a lender decision. Mortgage programs can allow different ratios based on credit profile, reserves, loan type, compensating factors, and underwriting system results. A result inside the rule does not promise approval, and a result above it does not always mean denial.

After this ratio screen, use the Mortgage Calculator to build a principal, interest, tax, and insurance payment estimate for the housing input.

The calculator turns monthly income and debt payments into two percentages, then reports the lower monthly housing limit from the selected front-end and back-end targets.

• Gross monthly income: Monthly income before taxes, insurance deductions, retirement contributions, or other payroll reductions.
• Monthly housing payment: The proposed recurring housing cost. For a mortgage estimate, use principal, interest, taxes, insurance, mortgage insurance, HOA dues, and similar required property charges when available.
• Other monthly debt: Recurring debt payments that are not part of the proposed housing payment, such as auto loans, student loans, personal loans, and minimum credit card payments.
• Ratio limits: The default targets are 28% for housing and 36% for total debt, but the fields can be changed for a lender, program, or personal comfort target.

If the allowed housing room is lower than your proposed payment, the difference is the monthly overage against the stricter side of the rule. If the allowed room is zero, other debts already consume the selected back-end debt limit before any new housing payment is added.

The default front-end and back-end limits are not current interest rates or government benefit thresholds. They are planning ratios. Keep lender-specific guidance separate from the personal budget decision you make after seeing the ratios.

According to New Jersey Department of Banking and Insurance, the 28/36 qualifying ratio allows up to 28% of monthly pre-tax gross income for housing expenses and up to 36% for housing plus recurring debt.

According to Fannie Mae Selling Guide B3-6-03, monthly housing expense for the subject property is PITIA and includes principal and interest, applicable insurance premiums, real estate taxes, association dues, and certain subordinate financing payments.

If you need a monthly payment from home price, down payment, rate, and term first, the Home Loan Calculator supplies the payment estimate that belongs in this calculator.

The rule is easier to use when the two ratios and the housing-payment definition stay separate.

For the housing input, use a full monthly housing estimate when possible. A principal-and-interest quote alone can understate the ratio if property tax, homeowners insurance, mortgage insurance, or dues are missing.

For the other-debt input, use recurring monthly payment obligations rather than total balances. A large balance with a small required payment affects DTI differently than a small balance with a large monthly installment.

Because the rule uses gross income, compare the result with take-home cash flow in the Budget Calculator before treating the payment as comfortable.

Use monthly numbers throughout. Annual income, annual insurance, and annual taxes should be converted before entry.

1. 1 Enter gross monthly income: Use income before payroll deductions. If income is annual, divide by 12 before entering it.
2. 2 Enter proposed housing: Use the monthly payment estimate that includes principal, interest, taxes, insurance, mortgage insurance, and required dues when those amounts are known.
3. 3 Add other debt payments: Enter recurring monthly debts outside the proposed housing payment, such as auto, student, personal loan, and minimum card payments.
4. 4 Adjust limits only when needed: Leave 28 and 36 for the traditional screen, or change them to test a lender, program, or personal target.
5. 5 Read both ratios: Check whether the housing ratio or total DTI is driving the result before deciding what to change.
6. 6 Use the room number: A positive amount means the proposed payment is below the stricter limit; a negative amount shows the monthly reduction needed to fit the selected guideline.

Suppose a household earns $6,000 gross per month, has $700 in other debt, and is considering a $1,900 housing payment. The housing ratio is above 28%, and total DTI is above 36%, so the calculator points to both a lower housing payment and lower recurring debt as possible pressure points.

For an auto, personal, or student loan that affects the back-end ratio, estimate the monthly obligation with the Loan Payment Calculator.

The result helps turn mortgage affordability into monthly decisions you can compare and revisit. Run the 28 36 rule calculator again whenever debt payments or housing estimates change.

• • Separates two constraints: You can see whether housing cost or other debt is the tighter limit instead of treating DTI as one blended number.
• • Supports payment shopping: Use the allowed monthly housing room while comparing interest-rate quotes, insurance estimates, tax assumptions, and dues.
• • Frames debt payoff choices: If the back-end ratio is the blocker, reducing recurring debt may improve payment room more than lowering the home price alone.
• • Creates a personal checkpoint: The traditional rule can be stricter than some loan programs, so it gives a conservative checkpoint before stretching a monthly budget.
• • Documents assumptions: Keeping income, housing, other debt, and ratio targets visible makes it easier to discuss the same scenario with a lender or housing counselor.

The calculator is most useful when paired with a realistic monthly payment estimate. A low home price can still produce a high housing ratio if taxes, insurance, mortgage insurance, or dues are significant.

The status label is deliberately plain. It tells you what the selected ratios say, while the ratio values show where the pressure comes from.

When two mortgage or debt options produce different monthly payments, compare their payment and interest tradeoffs with the Loan Comparison Calculator.

Several assumptions can change the result even when income and home price stay the same.

• • The calculator does not decide mortgage approval. It does not evaluate credit score, reserves, property type, down payment, loan-to-value ratio, employment history, or underwriting exceptions.
• • The result is only as reliable as the monthly payment inputs. Missing taxes, insurance, mortgage insurance, HOA dues, or debts can make the ratios look better than the full application picture.
• • The 28/36 screen uses gross income, so it does not show whether the payment feels manageable after taxes, childcare, utilities, savings, food, transportation, or medical costs.

A scenario above the rule can still be worth discussing with a qualified lender, especially when there are strong compensating factors. A scenario inside the rule still deserves a household budget check because gross income is not spendable cash.

When the result is close to the limit, rerun the numbers with less favorable assumptions: higher taxes, higher insurance, a slightly higher rate, or less monthly income. That stress test can reveal whether the payment has enough cushion.

According to Consumer Financial Protection Bureau, debt-to-income ratio compares your total monthly debt payments with your monthly gross income and helps lenders judge whether you can manage monthly payments.

For an existing mortgage that may be refinanced or paid down, the Mortgage Payoff Calculator helps separate payoff strategy from new-purchase affordability.