How to use this calculator
DTI is two ratios, not one: housing alone, and housing plus everything else. This tool computes both from gross income, then shows how much headroom remains under targets you choose — targets that are your budgeting choice, not a lender’s approval rule.
Enter your own figures in the form above. A blank field is treated as missing — not as zero — so the tool will ask you to complete it. A genuine zero is accepted where it makes sense (for example, no HOA dues). Press Calculate for a breakdown, Load worked example to fill in the example below, or Reset to return to the defaults.
Formula and assumptions
Front-end DTI = housing ÷ gross income. Back-end DTI = (housing + other debts) ÷ gross income. Headroom = target % × income − the corresponding cost. Income must be above $0; zero other debt is allowed.
Worked example
Worked example: $8,000 gross income, $2,000 housing, $800 other debts. Front-end DTI 25%; back-end DTI 35%. Against 28% / 36% targets, housing headroom is $240/month and total headroom is $80/month — the total ratio, not housing alone, is the binding constraint here.
Use the Load worked example button above to reproduce this example in the form, then change one input at a time to see what drives the result.
Limitations and common mistakes
Lenders calculate qualifying income and debts under program rules that differ from a household budget (for example, how variable income, deferred student loans or business debts are treated). This tool makes no approval or eligibility claim and no universal acceptance rule is asserted.
Frequently asked questions
Gross or net income?
Gross (before tax), as lenders generally use gross income for DTI. Using net income would overstate both ratios.
What counts as “other debts”?
Minimum monthly payments on cards, auto, student and personal loans, child support and similar obligations. Everyday spending is not a debt payment for DTI purposes.
Is a lower DTI always better?
For borrowing capacity, generally yes — but a very low DTI achieved by an unsustainably cheap home is not a goal in itself. Use DTI alongside a full budget.
Sources
Estimates only. Results from this calculator are not a loan offer, appraisal, engineering design, equipment selection or contractor quote.