What you'll need
- Gross monthly income (before taxes)
- Proposed mortgage payment (PITI + HOA)
- Monthly car, student loan, and credit card payments
- Any other monthly debt obligations
What you'll get
- Front-end DTI — Housing cost ratio
- Back-end DTI — Total debt ratio
- Max home payment — 28% and 36% rule limits
- Qualification assessment — Excellent, good, or high?
What the 28/36 rule allows, by income
| Gross Monthly Income | 28% Housing Ceiling | 36% Ceiling, No Other Debt | With $500/mo Debt | With $1,000/mo Debt |
|---|---|---|---|---|
| $5,000 | $1,400 | $1,800 | $1,300 | $800 |
| $6,000 | $1,680 | $2,160 | $1,660 | $1,160 |
| $8,000 | $2,240 | $2,880 | $2,380 | $1,880 |
| $10,000 | $2,800 | $3,600 | $3,100 | $2,600 |
| $12,500 | $3,500 | $4,500 | $4,000 | $3,500 |
These are the two figures this calculator returns — the 28% front-end ceiling, and the 36% back-end ceiling less your other monthly debt payments — and the lower of the two is the one that binds. They are a budgeting benchmark, not a lender's underwriting limit: loan programmes set their own maximums, many of them above 36%, and those are decided on your file by the lender you apply with.
Authoritative resources
State guides
How this varies by state
Property taxes, insurance costs, first-time buyer programs, and closing costs differ significantly across states. See local data for your state.
California
Texas
Florida
New York
Illinois
Pennsylvania
Ohio
Georgia
North Carolina
Michigan
New Jersey
Virginia
Washington
Arizona
Colorado
Tennessee
This calculator turns your numbers into two ratios: a front-end ratio (proposed mortgage payment ÷ gross monthly income) and a back-end ratio (that payment plus every other debt payment, ÷ the same income). It then grades each ratio against a single scale built into the tool — 20%, 28% and 36% — the same cutoffs for both ratios, not separate rules per loan program.
What the calculator actually adds up
The module takes seven inputs — gross monthly income, current rent, car payment, student loan, credit card minimum, other debt, and the proposed mortgage payment — and combines them in one place. Current rent is collected but never added to the debt total, because it disappears the day the new mortgage replaces it. Every other monthly obligation is summed into what the calculator calls non-housing debt, and that figure plus the proposed mortgage payment becomes total monthly debt.
Two companion figures come out of the same inputs: the calculator's maximum home payment at a 28% front-end ratio (gross income × 0.28), and its maximum home payment at a 36% back-end ratio (gross income × 0.36, minus whatever non-housing debt you already carry). The second number falls as your existing debt rises — it is the payment room your other obligations leave behind, not a fixed budget.
The status labels are one scale, applied twice
Both ratios are graded on the identical four-tier scale: 20% or under is excellent, up to 28% is good, up to 36% is borderline, and anything above 36% is high. That is a deliberate simplification. It does not vary by loan type, and there is no field on this page to tell it whether you are shopping conventional, FHA, VA or USDA — the calculator has no way to know, so it does not guess. What it gives you instead is a single, consistent yardstick you can apply to any offer and compare against your own numbers before a lender applies theirs.
That also means the 36% line is a genuinely conservative one. It is the boundary this specific tool uses to switch a back-end ratio from "borderline" to "high" — not a cutoff any single loan program publishes. Treat a "high" reading here as a flag to dig into your specific program's real limit, not as a rejection.
A worked example at the front-end cap
The same inputs also produce the calculator's 36%-based payment ceiling: $8,000 × 0.36 − $750 = $2,130. That is $110 below the $2,240 payment this borrower proposed. The front-end ratio says good; the calculator's own back-end-consistent number says the realistic room is $110/month lower. Reading both figures together, rather than either alone, is the point of running the two ratios side by side.
What isn't in this number
The "proposed mortgage" field is whatever payment you type into it. The calculator does not build that number up from a loan amount, term and rate, and it does not add estimated property tax, homeowners insurance, HOA dues or mortgage insurance on top. If you enter a bare principal-and-interest figure, both ratios understate what an underwriter will actually count — real DTI calculations are run against full PITI, not P&I alone.
It also has no concept of loan size relative to the conforming loan limit. FHFA set the 2026 baseline one-unit conforming limit at $832,750, rising to $1,249,125 in high-cost areas. A proposed mortgage payment large enough to imply a loan above that line is a jumbo loan, underwritten on its own program guidelines — a different situation than the conventional/FHA territory this tool's 36% line was chosen to approximate.
How to use this before you talk to a lender
- Build your proposed mortgage payment honestly — principal and interest at a real rate, not a placeholder. The current benchmark is Freddie Mac's Primary Mortgage Market Survey, which put the 30-year fixed average at 6.71% for the week ending September 3, 2026 (15-year fixed 6.04% the same week).
- Check both ratios, not just one. A front-end reading of good with a back-end reading of high means your other debts, not your target house, are the constraint — the fix is different in each case.
- Use the 36%-based maximum payment figure as your realistic ceiling for this tool's scale, and treat the front-end 28% ceiling as a secondary check, not the binding one, whenever you carry any non-housing debt at all.
Methodology
Ratios and status labels are read directly from this calculator's own module: front-end DTI = proposed mortgage payment ÷ gross income; back-end DTI = (proposed mortgage payment + non-housing debt) ÷ gross income; status bands at 20%/28%/36% applied identically to both ratios. The worked example is computed with those same formulas. Rate context is Freddie Mac PMMS for the week ending September 3, 2026. Conforming loan limit figures are FHFA's 2026 announcement.
Sources
- Freddie Mac — Primary Mortgage Market Survey, week ending September 3, 2026 — accessed 2026-09-05
- FHFA — Conforming Loan Limit Values for 2026 — accessed 2026-09-05
Frequently asked questions
What is a good debt-to-income ratio for a mortgage?
This calculator applies the 28/36 rule: a front-end ratio (housing costs only) at or below 28% of gross monthly income, and a back-end ratio (all debts) at or below 36%. It labels anything above 36% high. Loan programmes and individual lenders set their own maximums, and many of them sit above 36% depending on credit, reserves and the automated underwriting decision on your file — those ceilings are set in investor guidelines that change, so ask the lender you are applying to rather than relying on a published figure.
What is front-end vs back-end DTI?
Front-end DTI (housing ratio) is your proposed monthly housing payment divided by gross income. Back-end DTI (total debt ratio) includes all monthly debt payments — housing, car, student loans, credit cards — divided by gross income. Lenders look at both.
How can I lower my DTI before applying for a mortgage?
You can lower your DTI by paying off debt (especially high-payment debts like car loans), increasing your income, or choosing a less expensive home. Paying off a car loan or credit card can significantly reduce your back-end DTI and improve your chances of approval.
Does my DTI include the new mortgage payment?
Yes — your back-end DTI includes the proposed new mortgage payment (P&I + taxes + insurance + HOA) plus all existing monthly debt obligations. Lenders calculate DTI using the total payment you'd have after closing, not your current housing cost.
What DTI does the 28/36 rule refer to?
The 28/36 rule is a budgeting guideline: spend no more than 28% of gross income on housing (front-end DTI) and no more than 36% on all debts combined (back-end DTI). Those are the two lines this calculator computes, and its “maximum housing payment” figures are the 28% ceiling and the 36% ceiling less your other debt payments. Lenders will often approve above 36% on the back-end ratio; this calculator does not model those exceptions, so treat the 36% line as a budgeting benchmark rather than an approval threshold.