28/36 Rule Calculator
Print| Max Total Monthly Debt Limit (36%) | $0.00 / mo |
| Max Non-Housing Debt Allowance (8%) | $0.00 / mo |
Determine your home loan qualification thresholds before applying for a mortgage. Use this 28/36 Rule Calculator to calculate your maximum recommended monthly housing payment (28% front-end ratio) and total debt-to-income limit (36% back-end ratio) based on underwriting standards.
The Formula Behind the 28/36 Budgeting Rule
The 28/36 rule is a classic mortgage underwriting benchmark used by lenders to evaluate borrower financial health and loan safety:
Max Monthly Housing Payment (Front-End 28%) = Gross Monthly Income × 0.28
Max Total Monthly Debt Payment (Back-End 36%) = Gross Monthly Income × 0.36
Max Affordable Mortgage PITI = Min( Front-End 28% Cap, (Back-End 36% Cap - Existing Monthly Debts) )
Where:
- Gross Monthly Income: Pre-tax monthly earnings from salary, bonuses, and reliable secondary income.
- Housing Expenses (PITI): Principal, Interest, Property Taxes, Homeowners Insurance, and HOA dues.
- Existing Monthly Debts: Car loans, student loans, minimum credit card payments, personal loans, and child support.
28/36 Rule Qualification Matrix across Income Levels
Refer to the lookup table below for maximum allowable housing payments and total debt caps across common gross income levels assuming $500/month in existing recurring debt:
| Annual Gross Income | Monthly Gross Income | Max Housing Payment (28% Front-End) | Max Total Debt Limit (36% Back-End) | Max Qualified Housing (with $500 Debt) |
|---|---|---|---|---|
| $60,000 | $5,000 | $1,400 / month | $1,800 / month | $1,300 / month ($1.8k – $500) |
| $85,000 | $7,083 | $1,983 / month | $2,550 / month | $1,983 / month (Front-end capped) |
| $110,000 | $9,167 | $2,567 / month | $3,300 / month | $2,567 / month (Front-end capped) |
| $150,000 | $12,500 | $3,500 / month | $4,500 / month | $3,500 / month (Front-end capped) |
Step-by-Step 28/36 Rule Example
Consider a buyer earning $90,000 per year ($7,500 monthly gross income) carrying a $400 monthly car payment and $250 monthly student loan payment ($650 total existing recurring monthly debt):
- Calculate Front-End 28% Housing Limit: $7,500 gross income × 0.28 = $2,100 maximum monthly housing payment (PITI).
- Calculate Back-End 36% Total Debt Limit: $7,500 gross income × 0.36 = $2,700 maximum combined debt payments.
- Check Back-End Constraint: $2,700 total debt limit – $650 existing debts = $2,050 maximum available for housing.
- Determine Final Qualified Housing Budget: Compare front-end ($2,100) vs back-end constraint ($2,050). The lower limit applies: $2,050 per month maximum housing payment.
Frequently Asked Questions
What is the difference between front-end DTI and back-end DTI?
Front-end DTI measures only your prospective housing costs (mortgage principal, interest, taxes, insurance) relative to gross income. Back-end DTI measures all monthly debt obligations combined (housing plus car payments, student loans, credit cards) relative to gross income.
Do all mortgage lenders enforce the 28/36 rule strictly?
While the 28/36 rule is a standard benchmark for conventional loans, government-backed loans like FHA (allowing up to 31/43 or 46/57 with compensating factors) and VA loans offer more flexible DTI limits.
How can I improve my 28/36 DTI ratio before applying for a mortgage?
To improve your DTI ratio, pay off high-principal consumer debts (auto loans or credit cards) to lower your monthly recurring liabilities, or increase your down payment size to reduce prospective monthly mortgage principal.
Are utility bills included in the 28/36 calculation?
No, recurring utility bills (electricity, water, internet) and groceries are not classified as debt liabilities and are not included in front-end or back-end DTI calculations.