What DTI is and why lenders look at it
DTI stands for Debt-to-Income, the ratio between a person's total monthly debt payments and their gross monthly income. It's one of the main metrics lenders use to decide whether to approve a new loan: the larger the share of income already tied up in debt, the smaller the cushion for handling unexpected expenses, and the riskier it is to lend that person more money.
Formulas used
Overall DTI: DTI (%) = (total monthly debts ÷ gross monthly income) × 100
Front-end (housing) DTI: front-end (%) = (housing expense ÷ gross monthly income) × 100
Back-end (total) DTI: back-end (%) = ((housing expense + other debts) ÷ gross monthly income) × 100
Room for new debt: available room = (income × target max DTI ÷ 100) − current debts
Practical example: overall DTI
With $6,000 in gross monthly income and $1,800 in total monthly debts (loan payments, credit cards, personal loans), the DTI is 30%, which is generally classified as manageable by most lenders, though it's already approaching the more comfortable limit.
Practical example: front-end vs back-end DTI
With that same $6,000 income, a $1,500 housing expense, and $800 in other debts, the front-end DTI is 25% and the back-end DTI is 38.3%. Lenders often have separate limits for each: rules like "housing up to 28% of income, total up to 36%" are common, and going over either limit can make approval harder, even if the other ratio looks fine.
Practical example: room for new debt
With a $6,000 income, $1,200 in current debts, and a target maximum DTI of 36%, the maximum allowed total debt is $2,160 (36% of $6,000). Since there's already $1,200 in debt, there's still room for $960 more in monthly payments before hitting that limit — useful for figuring out, say, the maximum payment on a new loan that still keeps DTI within target.
The classification bands used in this calculator
A DTI up to 20% is generally classified as excellent, indicating plenty of budget room. Between 21% and 35%, DTI is considered manageable by most lenders. Between 36% and 43%, DTI is already at the limit, and some lenders may hesitate to approve new credit or require stricter terms. Above 43%, DTI is considered high risk, making new loan approvals more difficult.
What this calculator doesn't account for
These calculations use gross income, but some lenders calculate DTI based on net (after-tax) income, which can produce a different percentage. Exact approval criteria also vary widely between lenders and loan types. Use the results as a planning reference, and confirm the specific criteria directly with the lender.