Largest mortgage loan affordable at target DTI

DTI as the Mortgage Ceiling

Debt-to-income ratio is the single most influential affordability number. Most lenders cap combined DTI (total debt payments divided by gross income) at 36-43 percent. The mortgage payment must fit inside that cap alongside any existing debts. This calculator works backward from that constraint to the maximum loan amount.

Adjusting the DTI Target

Default 36 percent is a conservative target. Some lenders allow up to 43 percent on conforming loans and 50 percent on VA or FHA loans. Entering a higher DTI gives a larger maximum loan but tighter monthly cashflow after closing. For comfort, staying below 36 percent leaves meaningful buffer for emergencies.

Quick example

With gross monthly income of 8,000 and existing monthly debt payments of 600 (plus interest rate of 6.5 and loan term of 30), the result is 333,495.00. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Gross Monthly Income, Existing Monthly Debt Payments, Interest Rate, Loan Term, and Max DTI Target. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

What's happening under the hood

Calculates maximum monthly mortgage payment as (gross monthly income times DTI percent) minus existing debts, then converts to principal via standard amortization formula. Results are estimates for illustration purposes only and do not factor property taxes, insurance, or PMI. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

Why this matters before you sign

A mortgage is usually the biggest single financial commitment a person makes. The difference between a well-chosen product and a hasty one can run into tens of thousands over the life of the loan. Running the numbers here before committing is the cheapest form of due diligence available.

What this doesn't capture

The figure excludes arrangement fees, valuation costs, legal fees, insurance, and any early-repayment charges — those can add several thousand to the headline cost. Rate changes at renewal for fixed-term deals will shift the picture further. Use this for the core interest/principal math and add the other costs on top.