What DTI means, in plain words
Your debt-to-income ratio, or DTI, is your monthly debt payments divided by your gross monthly income, the amount before taxes. Lenders look at it two ways. The housing ratio counts only the new house payment: principal and interest, property tax, homeowners insurance, mortgage insurance and HOA dues. The total ratio adds the rest of your debts: car loans, student loans, card minimums, child support and alimony. Rent you will stop paying, utilities, phone bills and groceries do not count.
So if you earn $9,000 a month before taxes and pay $600 a month on a car and student loans, those debts already use about 7% of your income before the house.
The three bands, and where they come from
| Band | Housing | Total | Where it comes from |
|---|---|---|---|
| Comfortable | 28% | 36% | The 28/36 rule of thumb. 36% is also Fannie Mae's base limit for a manually underwritten loan. |
| Typical | No separate cap | 43% | A common guideline, and the general QM limit until the CFPB replaced it with a price-based test in 2021. |
| Stretch | No separate cap | Up to 50% | Fannie Mae's maximum through Desktop Underwriter, with strong compensating factors. |
The 43% history is from the CFPB's General QM final rule, effective March 1, 2021 (linked in the sources under the calculator). Source: Fannie Mae Selling Guide B3-6-02, Debt-to-Income Ratios (April 2, 2025).
In my experience, a file in the typical band is routine when credit and savings are solid. The stretch band needs more: a strong score, money left after closing, sometimes a larger down payment. FHA, VA and USDA loans set their own limits, and part of my job is telling you which one fits your file.

Why the town changes the answer
Property tax sits inside the housing payment, so the same budget buys less house where the mill rate is high. For every $100,000 of appraised value, the yearly tax is about $686 in Salisbury, $2,007 in Milford and $4,897 in Hartford. Try each town on your list; the difference in what you can afford is often bigger than buyers expect.
Down payment, PMI and cash to close
With less than 20% down on a conventional loan, PMI is added to the payment. The calculator starts it at 0.6% of the loan a year, the middle of Freddie Mac's typical range, and you can change it. Keep cash for closing too: the attorney, title insurance, recording fees and prepaids. The mortgage calculator estimates those for any town, and each band above links straight to it. CHFA down payment assistance can help eligible buyers with both.
How much house can I afford, or how much should I borrow?
A lender's maximum is not a budget. DTI ignores child care, retirement savings, commuting and the repairs every older Connecticut house needs, so many buyers settle at the comfortable band on purpose. Once you have a range, a pre-approval turns it into a number backed by your credit and documents, which is what sellers and agents want to see.
What this leaves out
- Your credit score, which moves the rate, the PMI cost and how far a lender will stretch.
- Loan limits. Conforming and FHA limits cap the loan by county; see FHA loans in Connecticut.
- Savings left after closing, which lenders call reserves.
- Fire and special district taxes, and condo special assessments.
- How income is counted. Overtime, bonus and rental income need a history, and self-employed borrowers are figured differently.