Debt-to-income ratio calculator
Front-end and back-end DTI, compared with 28/36, FHA 31/43 and Fannie Mae limits.
- ๐บ๐ธ US federal & state rules
- Fannie Mae Selling Guide B3-6-02
- See sources
Back-end DTI
35.3%
Front-end (housing only): 28%
- Front-end DTI
- 28%
- Gross monthly income
- $7,500
- Total monthly debt
- $2,650
- Room under 36%
- $50
This is an example. Enter your numbers above and press the button to see your own result.
How you compare
| 28/36 rule of thumb | Within |
|---|---|
| FHA common guideline 31/43 | Within |
| Fannie Mae manual underwriting (36% total) | Within |
| Fannie Mae manual, strong credit and reserves (45% total) | Within |
| Fannie Mae Desktop Underwriter (50% total) | Within |
- Use gross monthly income, before taxes. Count minimum payments on loans and cards, child support and alimony. Leave out utilities, phone and groceries.
- Housing means principal, interest, property tax, homeowners insurance, mortgage insurance and HOA dues.
- Fannie Mae limits are from its Selling Guide. The FHA 31/43 figures are the commonly cited manual underwriting guideline; automated approvals can go higher. Lenders may set stricter limits.
Show the math
| Front-end | $2,100 รท $7,500 = 28% |
|---|---|
| Back-end | ($2,100 + $550) รท $7,500 = 35.33% |
What to do next
How it works
Front-end DTI is your monthly housing payment divided by gross monthly income. Back-end DTI adds your other monthly debt payments before dividing. Both use income before taxes.
The table compares your ratios to the 28/36 rule of thumb, the FHA 31/43 guideline and the Fannie Mae limits for conventional loans.
Things to keep in mind
These are maximums, not targets. Automated approvals can allow higher ratios with good credit, and many lenders add their own stricter limits.
Sources
Rules applied as of 2026-10-19. See the sources below for details.
- Fannie Mae Selling Guide B3-6-02, Debt-to-Income RatiosChecked 2026-10-19
- CFPB: What is a debt-to-income ratio?Checked 2026-10-19
Frequently asked questions
How do I calculate my debt-to-income ratio?
Add up your monthly debt payments and divide by gross monthly income. $2,650 in payments on $7,500 of income is a 35.3% DTI.
What is front-end vs back-end DTI?
Front-end counts only housing costs. Back-end adds every other debt payment. Mortgage lenders focus mostly on back-end.
What DTI do I need for a mortgage?
Fannie Mae allows up to 36% on manually underwritten loans, 45% with strong credit and reserves, and 50% through its Desktop Underwriter system. FHA guidelines commonly cite 31% housing and 43% total for manual approvals.
What counts as debt?
Loan and minimum credit card payments, child support and alimony. Utilities, phone bills, groceries and insurance other than homeowners are not counted.