Practical guide
Understanding debt-to-income check — two-scenario comparison
Everyday editorial team · GEOINNOVATION CO., LTD · Published · Updated
What this calculation is for
Debt-to-income ratio compares recurring debt obligations with gross monthly income. It is a useful screening measure before applying for financing, but it is not the same as a household cash budget. A lender can reject an application even when this ratio looks low.
How the method works
The housing payment, other counted monthly debts and proposed new debt are added and divided by gross monthly household income. The result is compared with the target percentage you enter. Different underwriting programs define counted debts and qualifying income differently.
A worked example
A $2,000 housing payment plus $500 of other debt against $8,000 gross monthly income produces 31.25% before another loan. Adding a $400 payment raises the ratio to 36.25%.
Assumptions and real-world differences
The target is user-selected, not an approval threshold promised by a lender. Credit history, reserves, employment, property costs and loan type are outside this calculation. Gross income must be positive, and annual income should be divided by 12 before entry.
Building two independent scenarios
Scenario A and Scenario B each have a complete set of inputs for this debt-to-income check calculation. Change several inputs in B when comparing genuinely different plans, then inspect the B-minus-A headline difference and the detailed rows. When multiple inputs change, the total difference cannot be attributed to just one of them.
Reproduce this tool’s example
These fixed example inputs are independent of edits you make above. Enter them in this tool to reproduce the result, then replace them with your own assumptions.
- Scenario A — Gross monthly household income
- 10,000 $
- Scenario A — Proposed monthly housing payment
- 2,800 $
- Scenario A — Other monthly debt payments
- 850 $
- Scenario A — New monthly debt payment
- 250 $
- Scenario A — Target total DTI
- 36 %
- Scenario B — Gross monthly household income
- 12,500 $
- Scenario B — Proposed monthly housing payment
- 2,800 $
- Scenario B — Other monthly debt payments
- 850 $
- Scenario B — New monthly debt payment
- 250 $
- Scenario B — Target total DTI
- 36 %
Scenario B result: 31.2%
Scenario A: 39.0%. Total debt-to-income ratio.
- Scenario A main result: 39.0%
- Scenario B main result: 31.2%
- Numeric difference (B − A), in result units: -7.8
Frequently asked questions
- Should I use net income?
- This DTI tool uses gross monthly income. Use a separate budget to test actual take-home affordability.
- Are utilities counted as debt?
- Lender definitions vary; follow the applicable program rather than assuming every monthly bill is a debt obligation.
- Why is this different from the one-factor comparison?
- The one-factor tool changes only gross monthly household income. This version lets all model inputs differ, so it is more flexible but does not isolate the effect of any single change.