Quick reference
How DTI is calculated
DTI divides your total monthly debt obligations by your gross monthly income — your income before tax and other deductions. Debt obligations included in the calculation are: mortgage or rent payment, minimum credit card payments, car loan payments, student loan payments, personal loan payments, and any other recurring debt obligation with a fixed repayment schedule.
Expenses that are not debt — utility bills, grocery spending, insurance premiums, subscriptions — are excluded from the numerator. DTI measures only formal debt obligations, not total cost of living.
Gross monthly income includes salary, self-employment income, rental income, pension income, and any other regular income sources before tax. Net income is not used because lenders apply their own tax calculations and want a pre-deduction baseline for comparison across applicants in different tax situations.
For mortgage applications in the Netherlands, lenders calculate DTI against the toetsinkomen — the income used for affordability testing — which may differ from gross salary depending on employment type, age, and other factors.
DTI formula
Front-end vs back-end DTI
Mortgage lenders in some markets — particularly the US and UK — distinguish between two DTI calculations.
Front-end DTI (also called the housing ratio) includes only housing costs: mortgage principal and interest, property tax, insurance, and any HOA or service charge. This measures how much of income goes purely to housing.
Back-end DTI includes all debt obligations — housing costs plus all other debt payments. This is the more comprehensive measure and the one most commonly referred to when discussing DTI in a lending context.
In the Netherlands, the mortgage affordability calculation is based on a notional monthly payment derived from the full mortgage amount at a standard test interest rate, not the actual contractual payment. This produces a conservative DTI figure that protects borrowers against future rate rises. Dutch lenders use the woonquote (housing ratio) — the percentage of gross income that can be allocated to housing — rather than a strict DTI threshold.
Worked examples
Total monthly debt payments: 1.100 + 280 + 75 + 120 = 1.575. DTI: 1.575 / 4.500 x 100 = 35%. This borrower is at the upper end of the acceptable range. Most mainstream mortgage lenders would still approve at 35% DTI, but there is limited room for additional borrowing. Reducing the car loan or clearing the credit card balance would improve the position.
Current: 1.670 / 5.000 = 33,4%. After paying off car loan: 1.320 / 5.000 = 26,4%. A 7 percentage point improvement in DTI. At 26,4%, this borrower moves from the upper-acceptable range to the comfortable range. If applying for a mortgage top-up or personal loan, this improvement significantly strengthens the application. Total cost to clear the car loan would need to be weighed against the improved borrowing capacity.
For self-employed borrowers, lenders typically use a 3-year average of taxable profit rather than the most recent year's income. If income was 4.200, 3.600, and 3.600 over three years, the average is 3.800. DTI: 1.050 / 3.800 = 27,6%. This is a comfortable DTI but the income calculation methodology means the effective income used by the lender is lower than the current year income, which affects maximum borrowing capacity even with an acceptable DTI.
Debt-to-Income Calculator
Enter your monthly income and debt payments to calculate your DTI and see where you stand against lender thresholds.
DTI thresholds and what they mean
| DTI Range | Classification | Lender View | Action |
|---|---|---|---|
| Below 20% | Excellent | Strong position — best rates available | No action needed |
| 20 to 28% | Good | Comfortable — most loans approved | Maintain current position |
| 29 to 35% | Acceptable | Approved for most products | Consider reducing before major borrowing |
| 36 to 43% | Elevated | Some lenders will decline | Reduce debt before applying |
| Above 43% | High | Most mainstream lenders decline | Significant debt reduction required |
Common mistakes with DTI
How to lower your DTI
There are two levers: reduce the numerator (debt payments) or increase the denominator (income). Income increases take time — salary growth, career progression, or additional income sources. Debt reduction is more controllable in the short term.
The fastest DTI improvements come from eliminating entire debt obligations rather than reducing balances. Paying off a car loan with a 350 monthly payment removes 350 from the DTI numerator immediately, regardless of the outstanding balance. By contrast, paying down a mortgage by 10.000 reduces the monthly payment by only approximately 50 to 60 — a much smaller DTI impact per euro spent.
For a mortgage application, the most effective pre-application strategy is to identify which debt has the highest monthly payment relative to remaining balance and eliminate that debt first. A 12-month-old car loan with 8 payments of 280 remaining costs 2.240 to clear but removes 280 from the monthly DTI calculation — a meaningful improvement for a relatively small outlay.
Methodology
DTI calculated as total monthly minimum debt payments divided by gross monthly income, expressed as a percentage. Thresholds based on standard European and US mortgage lending guidelines. Netherlands-specific affordability calculations reference the Nibud woonquote tables and AFM lending standards.
DTI thresholds vary by lender, product type, loan-to-value ratio, and applicant profile. The ranges shown are general guidelines. Always obtain a specific affordability assessment from a mortgage adviser or lender for your exact situation.
Calculate your DTI
Enter your monthly income and debt payments to see your DTI and where you stand against lender thresholds.
Frequently asked questions
Formula based on standard mathematical and financial methods. Results are for informational purposes. Last reviewed May 2026. Version 1.