Obtain monthly gross income (before taxes) from all borrowers
Add all required monthly debt payments (include: mortgage/rent, auto loans, student loans, credit cards minimums, personal loans, child support/alimony if applicable)
Compute total monthly debt payments
Divide total monthly debt payments by monthly gross income
Multiply the result by 100 to get DTI as a percentage
Use the formula:
DTI (%) = (Total monthly debt payments / Monthly gross income) × 100
For housing-only DTI (if needed):
Housing DTI (%) = (Monthly housing payment / Monthly gross income) × 100
Round to the desired precision (commonly one decimal place)