Tool · Investor Sam Debt

Debt-to-Income Ratio Calculator

July 1, 2026 • By the Investor Sam Editorial Team • Reviewed by Berly Sam Varghese, Editor
Debt-to-income ratio is the single number that most lenders examine first — it determines whether you can get a mortgage, auto loan, or personal loan, and at what rate. Most people do not know their own DTI until a lender rejects them. This calculator shows your front-end (housing only) and back-end (all debt) ratios, flags where you stand against the standard 28/36 thresholds, and tells you exactly how much monthly headroom you have before hitting the limit.

Example: Gross monthly income (before taxes): 6000 $ · Monthly housing payment (rent or mortgage): 1400 $ · Other monthly debt payments (car, student, credit cards): 500 $

Back-end DTI (all debt ÷ income)31.67%
Front-end DTI (housing ÷ income)23.33%
Total monthly debt obligations$1,900
Monthly headroom before 36% limit$260
Max additional housing you can afford$260

Worked example

On $6,000 gross monthly income, a $1,400 housing payment (front-end DTI = 23%) and $500 in other debt (back-end DTI = 32%) sit below the standard 28/36 thresholds — you look good to most lenders. But there is only $160/month of headroom before hitting 36%. Adding even a $200 car payment would push the back-end DTI to 35.3%, right at the edge. Knowing your headroom before you apply lets you plan, not react.

Frequently asked questions

What DTI do lenders actually require?

Conventional mortgages typically use 28% front-end and 36% back-end as qualifying guidelines, though Fannie Mae and Freddie Mac allow back-end DTI up to 45–50% with compensating factors such as strong credit or large reserves. FHA loans allow back-end DTI up to 57% in some cases. The thresholds vary by lender and loan type.

Does DTI affect my interest rate, or just my approval?

DTI primarily affects approval eligibility. Your interest rate is driven more by credit score, loan-to-value ratio, and loan type. However, a high DTI can push you toward loan programs with less favorable pricing, and some lenders use risk-based pricing that considers DTI as a secondary factor.

What counts as a debt in the back-end DTI?

Lenders include all monthly obligations reported on your credit report: mortgage or rent, auto loans, student loans, minimum credit card payments, personal loans, and child support or alimony. Utilities, insurance, subscriptions, and groceries are not counted.

How can I lower my DTI quickly?

Two levers: increase income (a second job, raise, or rental income counts if it can be documented for two years) or reduce debt (pay down balances to lower minimum payments, or close paid-off installment accounts). Paying off a car loan or a small credit card balance can move DTI meaningfully in a single month.

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Sources

Berly Sam Varghese · Editor, Investor Sam

Berly Sam Varghese is an engineer who treats money the way he treats any hard problem — something to be engineered, not gambled on. He funded years of education and built real financial stability the patient way, by living below his means and investing rather than borrowing. He writes for the person whose math looks impossible on paper — the corner he once engineered his own way out of. He reviews and approves every article on Investor Sam and checks the figures against primary sources before anything is published. More about our standards.