Debt-to-Income Ratio Calculator

The calculation is DTI = monthly debt payments ÷ gross monthly income, expressed as a percentage. Its simplicity is the source of both its usefulness and its blind spots. What counts as a debt payment is narrower than what counts as a bill. Included are required recurring payments on borrowed money and housing: rent, or a mortgage payment with property taxes and homeowners insurance, plus car loans, student loans, personal loans and the minimum due on credit cards. Court-ordered obligations such as alimony or child support are typically counted too. Excluded is most of what you actually spend. Groceries, utilities, gasoline, phone plans, health insurance premiums, childcare, subscriptions and retirement contributions do not appear, even though they leave the account as reliably as a loan payment does. That exclusion list explains the ratio's single most important property: DTI is a measure of leverage, not of affordability. It tells a lender how much of your gross income is already promised to creditors. It does not tell anyone whether the remainder is enough to live on, and two households with identical ratios can be in very different positions.

Lenders read the ratio two ways, and both appear in the results above. The front-end ratio counts housing only — rent, or mortgage principal and interest plus property taxes and insurance, sometimes with HOA dues and mortgage insurance. The back-end ratio is the same denominator with every other required debt payment added, and it is the figure most people mean by "DTI". The traditional benchmark is 28/36: housing at or below 28% of gross income, total debt at or below 36%. This is an underwriting convention of long standing rather than a rule set by any regulator, and its value is as a reference point — the zone where applications are comfortable and where a budget generally still has room in it. Both numbers matter because they fail differently. A high front-end ratio with low other debt means the house itself is the stretch. A modest front-end ratio with a high back-end ratio means the house is fine and the car loan and cards are the constraint. The remedies are not the same, which is why lenders look at the pair rather than the total.

The 43% threshold is widely quoted as a mortgage ceiling, and it is worth being precise about what it is and is not. It entered common use through the federal ability-to-repay framework, under which lenders must make a reasonable, good-faith determination that a borrower can repay, and through the associated qualified mortgage standards that gave lenders defined ways to satisfy it. A 43% back-end DTI functioned as a bright line within that structure for a period, which is why the number became shorthand for "the cap". The rules defining qualified mortgages have been revised since, and the criteria a loan must meet are technical and have changed over time. Just as importantly, individual loan programs set their own limits, and several routinely accept ratios above 43% where other factors are strong — substantial reserves, a large down payment, or a high credit score. Others are stricter than 43%. The honest summary: treat 43% as a widely used reference point rather than a legal ceiling that applies to you. What actually binds is the program you apply to and that lender's overlays, and the only reliable way to learn it is to ask the lender directly. Approval odds and pricing generally worsen as the ratio climbs regardless of where the formal limit sits.

The denominator is gross monthly income — before income tax withholding, before Social Security and Medicare, before health premiums and retirement contributions. That is the convention lenders use, which is why this calculator uses it, and it means the ratio reads better than your bank balance does. The practical effect: a back-end DTI of 36% of gross can be a considerably larger share of take-home pay, and the exact gap depends on your own tax situation and deductions. A ratio that clears an underwriting threshold with room to spare can still leave a month that does not balance. A useful second pass is to recompute the same debt payments against your actual take-home pay. Enter your net monthly income in the income field and read the result as a personal stress test rather than a lender's view. Nothing about the arithmetic changes; only the honesty of the denominator does. One more input caution. Lenders count income they can document and expect to continue — a stable salary is straightforward, while bonuses, commissions, overtime and self-employment income are typically averaged over a period and supported by returns or statements. Entering an optimistic figure here produces an optimistic ratio that an underwriter will not reproduce.

Because DTI is a fraction, only two things change it. Shrink the numerator. The most efficient move is paying off a loan entirely, because the whole payment leaves the ratio at once — a $400 car payment cleared against $6,000 of gross income removes nearly seven points on its own. Paying a card balance down helps less directly but still helps, since a lower balance generally means a lower minimum, and it is the minimum that counts. Avoiding new financing in the months before a mortgage application matters more than people expect: a new car loan or a furniture installment plan taken out during underwriting can change the ratio enough to affect the decision. Grow the denominator. Documented, continuing income is the only kind that counts, so a raise reflected in pay stubs works while an expectation of one does not. Additional income sources generally need a history behind them before an underwriter will use them. The results above show the headroom left before hitting 36%: how much additional monthly debt payment would still keep you at or under that mark. Read it as a budgeting constraint rather than a target to fill. And note what the ratio still cannot see — a household with no debt at all and no savings scores a perfect DTI, which is a reminder that this is one indicator among several rather than a verdict on your finances.