Debt-to-Income Calculator
Estimate current and projected debt-to-income ratio, monthly debt capacity, and borrowing headroom with the WealthCalcLab debt-to-income calculator.
Updated April 10, 2026
What this calculator does
This debt-to-income calculator shows how much of your gross monthly income is already committed to debt payments and how much room remains before you cross your target ceiling.
It is useful before applying for a mortgage, personal loan, auto loan, or refinance because the ratio helps frame affordability and underwriting risk quickly.
The best use of the tool is not just to see the current ratio, but to compare your current position with the ratio you would carry after adding the next payment.
This page is built for users who need a defensible planning answer, not just quick arithmetic. It translates "Gross monthly income", "Housing payment", and "Other monthly debt payments" into "Current DTI", "Projected DTI", and "Remaining monthly debt capacity" so the trade-off is visible in one place instead of being hidden behind a single number.
How to use it
Enter gross monthly income first, then add your current housing payment and other required debt payments.
Set the target DTI ceiling you want to stay under, then use Advanced options if you want to test a proposed new monthly payment.
Read current DTI and projected DTI together so you can see whether the new loan still leaves breathing room.
Start with "Gross monthly income", "Housing payment", and "Other monthly debt payments", then check whether the first output cards already answer your question. After that, add advanced assumptions such as "Proposed new monthly payment" only when they are real enough to change the decision.
Formula
DTI = total required monthly debt payments / gross monthly incomeRemaining capacity = target monthly debt load - current required debt loadThe ratio is shown as a percentage so you can compare current debt load with the target ceiling directly.
Methodology
Debt-to-income ratio equals required monthly debt payments divided by gross monthly income.
Projected ratio adds the proposed new monthly payment on top of the current required debt load.
Remaining monthly debt capacity shows how much more required debt payment fits under the selected ceiling before you cross it.
The model maps "Gross monthly income", "Housing payment", and "Other monthly debt payments" into "Current DTI", "Projected DTI", and "Remaining monthly debt capacity" using the formulas shown on the page. Keeping those relationships visible makes it easier to separate the core economics from the optional adjustments and to understand which assumption is actually moving the answer.
Worked example
A borrower earning 6,200 per month with 2,100 of existing debt payments is already using a meaningful share of gross income before adding anything new.
If the next proposed payment pushes the projected ratio near the target ceiling, the monthly payment may still be technically possible but financially tight.
How to interpret the results
Current DTI shows your starting position. Projected DTI shows whether the next loan or housing payment pushes the structure into a riskier range.
Remaining monthly debt capacity is often the most practical output because it frames how much space is left before the target ceiling is breached.
Read "Current DTI" first, then use the other summary cards, the chart, and the detailed table to judge short-term affordability and long-term borrowing cost. In most finance decisions, the best option is the one that stays strong across the full picture, not just the one with the most attractive first number.
Common mistakes
- Using net income instead of gross income when comparing against lender-style DTI thresholds.
- Leaving out required housing costs or minimum debt payments.
- Treating a lender ceiling as the same thing as a comfortable personal cash-flow ceiling.
Key terms
Quick definitions for the finance terms that matter on this page.
Debt-to-income ratio
The share of gross monthly income already committed to required debt payments.
Debt capacity
The monthly payment room available before you cross a target DTI ceiling.
Frequently asked questions
Clear answers on assumptions, interpretation, and the limits of each estimate.
Is a lower DTI always better?
Lower is usually safer because it leaves more cash-flow buffer, but the right ceiling depends on income stability, savings, and the type of borrowing.
Should housing payment be included?
Yes. Rent or mortgage-style housing payments are usually a core part of debt-service analysis.
Does this equal loan approval?
No. Approval also depends on credit profile, assets, employment stability, and the lender's specific rules.
Should I use gross or take-home income?
Use gross income for DTI comparisons and take-home income separately when testing personal affordability.
Which inputs change "Current DTI" the most?
Start with "Gross monthly income", "Housing payment", and "Other monthly debt payments". Those assumptions usually drive "Current DTI" far more than any optional adjustment. Once the base case is right, use advanced inputs only to reflect real fees, taxes, or timing differences.
What does "Current DTI" tell me in practical terms?
"Current DTI" is the fastest read on the outcome, but it should not be treated as the whole decision by itself. Use it as the headline number, then read the chart, table, and other summary cards to understand what is happening underneath.
Why should I look at "Projected DTI" as well as "Current DTI"?
Because "Current DTI", "Projected DTI", and "Remaining monthly debt capacity" answer different parts of the same decision. A scenario can look good on the first number and still be weak once timing, total cost, or long-run value is included.
When should I use "Proposed new monthly payment"?
Use "Proposed new monthly payment" when it materially changes the economics of the decision. If it is uncertain or optional, compare the base case with and without it rather than guessing once and trusting the result.
What happens if the advanced options stay at zero?
Then the calculator runs a simpler base case using the main inputs only. That is often the best place to start, because it makes it easier to see what changes once optional costs, fees, taxes, or adjustments are layered in.
Does the chart add anything beyond the summary cards?
Yes. The chart shows how the result develops over time, which is often the real decision point. It is especially useful when two scenarios have a similar headline result but very different timing or cost patterns.
What is the detailed table useful for?
Use the table when you need the period-by-period breakdown behind the summary. That is usually where users spot front-loaded interest, a slow payoff path, a contribution gap, or the exact point where one scenario becomes better than another.
Should I compare more than one borrowing readiness?
Yes. A base case and one stressed case usually give a much better planning view than a single run. Change one major assumption at a time so you can see what is actually responsible for the difference.
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Important disclaimer
For Bulgaria, confirm local treatment of lender fees, repayment timing, and any mortgage or prepayment rules before using the output for a final application, filing, or contract decision.