Debt-to-Income (DTI) Calculator
Calculate front-end and back-end DTI ratios to evaluate mortgage readiness and monthly debt capacity.
This DTI calculator helps you compare your monthly debt obligations to gross monthly income. Use it to estimate lender-style affordability thresholds and understand how much room you have for additional debt.
Calculator Inputs
Income before taxes and deductions
Rent or proposed mortgage payment (PITI if available)
Auto loans, student loans, credit cards, personal loans
Live Results
Breakdown
What Debt-to-Income (DTI) Means
Debt-to-income ratio compares your required monthly debt payments to your gross monthly income. Lenders use DTI to estimate repayment risk and borrowing capacity. Lower DTI usually means better approval odds and more flexibility in a housing budget.
DTI Formulas Used
Front-End DTI = Housing Payment / Gross Monthly Income × 100
Back-End DTI = (Housing Payment + Other Monthly Debt) / Gross Monthly Income × 100
Back-end DTI is generally the primary underwriting metric for mortgage decisions because it captures total required debt burden.
How to Improve DTI Before Applying
- Pay down revolving balances before new credit checks.
- Increase verified income (if stable and documentable).
- Avoid opening new financed obligations before underwriting.
- Recalculate with realistic PITI and minimum debt payments.
Frequently Asked Questions
What is the difference between front-end and back-end DTI?
Front-end DTI uses housing payment only. Back-end DTI includes housing plus all required monthly debt payments and is usually the stronger underwriting metric.
Is 43% DTI always the approval cutoff?
No. Program rules vary, and some loans allow different limits depending on compensating factors, reserves, and credit profile.
Should I use gross or net income in DTI?
Use gross monthly income for lender-style DTI calculations unless a specific program says otherwise.
Sources
- Consumer Financial Protection Bureau. What is a debt-to-income ratio? CFPB.gov
- Fannie Mae. Debt-to-income ratio guidance and underwriting context. FannieMae.com
- Freddie Mac. Credit and affordability overview for homebuyers. FreddieMac.com
Methodology and Limits
This tool uses transparent formulas and user-provided inputs to generate planning estimates in your browser. Results are for educational use and should be validated before making legal, financial, tax, or medical decisions.
Key Assumptions
- DTI uses gross monthly income (before taxes) and minimum required monthly debt payments.
- Front-end DTI includes housing only; back-end DTI includes housing plus other recurring debt.
- Approval standards vary by lender, loan program, credit profile, and compensating factors.
Primary References
Last methodology review: May 17, 2026.
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