Mortgage Qualifier Calculator
See the home price you can qualify for, based on your income, debts and a lender’s front-end and back-end debt-to-income limits.
A worked example
Running this tool on current national benchmarks (Federal Reserve / Freddie Mac via FRED (St. Louis Fed)) — swap in your own numbers to see how the result moves.
- Gross monthly income
- $8,000
- Monthly debt payments
- $600
- Down payment
- $60,000
- Interest rate
- 6.50%
- Loan term (years)
- 30
- Taxes + insurance (monthly)
- $450
- Front-end DTI limit
- 28%
- Back-end DTI limit
- 43%
$283,197 loan + $60,000 down
- Affordable payment (P&I)$1,790.00
- Maximum loan$283,197
- Limited byHousing ratio
How the home price you qualify for changes with gross monthly income
Holding the other inputs at the example above, here is how the result moves as gross monthly income changes.
| Gross monthly income | Home price you qualify for | Affordable payment (P&I) |
|---|---|---|
| $5,000 | $210,300 | $950.00 |
| $8,000 | $343,197 | $1,790.00 |
| $12,000 | $520,393 | $2,910.00 |
| $18,000 | $786,188 | $4,590.00 |
The math behind it
The calculator applies a lender's two debt-to-income limits. The front-end (housing) limit caps your housing cost at a share of gross monthly income; the back-end limit caps total debt including the mortgage. It subtracts taxes and insurance from the front-end room, and taxes, insurance, and other debts from the back-end room, then takes the lower of the two as your affordable principal-and-interest payment. That payment is converted to a maximum loan at your rate and term, and adding your down payment gives the home price you qualify for.
Assumptions & limits
- Two limits apply — a front-end housing ratio and a back-end total-debt ratio — and the tighter one governs. The defaults are 28% and 43%.
- Taxes and insurance are subtracted from the housing budget before the loan is sized; other monthly debts count only against the back-end limit.
- The affordable payment covers principal and interest; PMI, HOA dues, and closing costs are not modeled.
- A single fixed interest rate is assumed for the term.
- This estimates a lending ceiling from ratios alone. Real approval also weighs credit score, assets, employment, and loan program.
The 28/36 qualifying rule
A common conventional guideline. The calculator lets you adjust both limits.
| Ratio | Guideline |
|---|---|
| Front-end (housing) | Housing cost under 28% of gross income |
| Back-end (total debt) | All debt under 36% of gross income |
| Automated conventional | Back-end often stretched to 45% or higher |
Source: Freddie Mac PMMS via FRED. Annual averages; latest weekly reading shown.
Common questions
What is the difference between front-end and back-end DTI?
Front-end DTI counts only your housing payment against income; back-end DTI counts all monthly debt, including the mortgage, car loans, and credit cards. Lenders check both, and the lower resulting loan amount is what you qualify for. This calculator applies whichever is more limiting for you.
What is the 28/36 rule?
It is a common guideline: keep housing costs under 28% of gross income and total debt under 36%. Many conventional lenders now allow higher back-end ratios through automated underwriting, which is why the calculator lets you raise the limits — but 28/36 remains a conservative benchmark.
Why does the calculator say I am limited by a specific ratio?
It reports whether the housing ratio or the total-debt ratio produced the smaller allowable payment. If you are limited by the total-debt ratio, paying down other debts frees up borrowing room; if limited by the housing ratio, only income or a lower rate helps.