What a debt-to-income ratio is and why lenders use it
Your debt-to-income ratio (often called DTI) is a percentage that shows how much of your monthly income goes toward debt payments. Lenders calculate it by adding up all your monthly debt obligations and dividing by your gross monthly income — the money you earn before taxes and deductions.
Lenders use this number because it predicts whether you can handle a new loan. If you already spend 50% of your income on debt, a mortgage lender knows you have little room left for a house payment. The ratio tells them your risk level as a borrower.
Different types of loans have different DTI limits. Mortgage lenders typically want to see a ratio below 43%, though some will go higher. Credit card companies, auto lenders, and personal loan providers each have their own thresholds, and those thresholds vary by lender.
Key Takeaways
- Debt-to-income ratio is calculated by dividing your total monthly debt payments by your gross monthly income and converting to a percentage.
- Monthly debt payments include mortgage or rent, car loans, student loans, credit card minimums, and personal loans — but not utilities or groceries.
- Gross income means your earnings before taxes, and includes salary, wages, self-employment income, and regular benefits.
- Most mortgage lenders want a DTI below 43%, but the acceptable ratio varies by loan type and by individual lender.
- You can lower your ratio by paying down debt or increasing your income, and both approaches take time.
The formula and what counts as debt
The calculation itself is straightforward: add up all your monthly debt payments, divide by your gross monthly income, then multiply by 100 to get a percentage.
Monthly debt payments that count include mortgage or rent payments, car loan payments, student loan payments, credit card minimum payments, personal loan payments, and any other loan installments. Some lenders also count alimony or child support. What does not count: utilities, groceries, insurance premiums (unless they are part of a loan payment), phone bills, or gas.
The reason rent counts is important: even though you do not own the home, the payment is a fixed monthly obligation that reduces the money available for other debts. Mortgage payments count the same way.
For credit cards, lenders use the minimum payment amount, not the full balance. If your card has a $5,000 balance but a $100 minimum payment, only the $100 goes into the calculation. This is why paying down credit card balances can lower your ratio even if your income stays the same.
How to calculate your own ratio step by step
Step 1: Find your gross monthly income. If you are salaried, divide your annual salary by 12. If you are paid hourly, multiply your hourly rate by the number of hours you typically work per week, then by 52 weeks, then divide by 12. If you are self-employed, use your average monthly income from the past two years. Include regular income from benefits, pensions, or side work.
Step 2: List all monthly debt payments. Write down the minimum payment for each credit card, the monthly payment for your mortgage or rent, your car loan payment, your student loan payment, and any other loan payments. Do not estimate — use the actual amounts from your statements or payment confirmations.
Step 3: Add them up. Total all the monthly payments from Step 2.
Step 4: Divide and convert. Take your total monthly debt payments and divide by your gross monthly income. Multiply the result by 100. That is your debt-to-income ratio as a percentage.
Example: If your gross monthly income is $4,000 and your total monthly debt payments are $1,200, your calculation is ($1,200 ÷ $4,000) × 100 = 30%. Your debt-to-income ratio is 30%.
What lenders actually look at: front-end and back-end ratios
Many lenders, especially mortgage lenders, calculate two different ratios instead of just one. Understanding the difference matters because one might disqualify you even if the other looks good.
The front-end ratio (also called the housing ratio) includes only your housing payment — mortgage, property taxes, homeowners insurance, and mortgage insurance if applicable. Lenders typically want this below 28% of your gross income. This ratio tells them whether the house payment alone is affordable.
The back-end ratio (also called the debt-to-income ratio) includes your housing payment plus all other debts. Most mortgage lenders want this below 43%, though some will accept up to 50% if you have other strengths like a large down payment or excellent credit. This ratio shows whether you can handle the house payment and everything else you owe.
A mortgage process might be denied if your back-end ratio is acceptable but your front-end ratio is too high — meaning the house payment itself is too large relative to your income, even though your total debt load is manageable.
Why self-employed income and variable income complicate the calculation
If you are self-employed or earn variable income (commission, tips, seasonal work), lenders do not use your gross income as stated on a single recent paycheck. Instead, they average your income over the past two years using tax returns. This protects them from lending based on a single good month.
Some lenders will average the past 24 months of income; others use the past two years of tax returns. If your income has been rising, this method may show a lower income than you currently earn. If your income has been falling, it may show higher income than you currently earn.
Bonus income, commission, and overtime are treated the same way — averaged over two years. If you have been receiving a bonus for only six months, most lenders will not count it yet. This is why self-employed borrowers often need to wait two years of consistent income before they can show lenders a strong process.
How to improve your debt-to-income ratio
If your ratio is too high for the loan you want, you have two paths: lower your debt or raise your income. Both take time, but they work.
Lowering debt: Pay down credit card balances first, since they count as their minimum payment amount. Paying a $5,000 balance down to $2,500 might lower your minimum payment from $100 to $50, which when ready improves your ratio. Paying off a car loan or personal loan removes that payment entirely. Do not close credit card accounts after paying them off — closing them can hurt your credit score and may actually raise your ratio by reducing your available credit.
Raising income: A salary increase, a second job, or a promotion all raise your gross monthly income, which lowers your ratio. If you are self-employed, documenting higher income on your tax returns takes time — you will need to show two years of the higher income before lenders will use it.
Timing matters: If you are planning to explore for a mortgage or large loan, start improving your ratio at least six months in advance. Paying down debt takes time to show on your credit report, and lenders pull recent statements. A payment you made last week might not appear on your credit card statement for another month.
What happens if your ratio is too high
If a lender tells you your debt-to-income ratio is too high, you have a few options. You can wait and improve the ratio before reapplying. You can look for a lender with a higher acceptable ratio — some credit unions and portfolio lenders (lenders who keep loans rather than selling them) are more flexible. You can add a co-borrower with income, which raises the total income used in the calculation.
Some mortgage lenders will approve you with a higher ratio if you have compensating factors: a large down payment, excellent credit, significant savings, or a stable employment history. Ask the lender what factors they consider.
If you are denied for a loan, the lender must provide a written reason. That reason will tell you whether your ratio was the issue or whether other factors like credit score or employment history played a role.
Frequently Asked Questions
Do student loan payments count toward my debt-to-income ratio?
Yes. Lenders count your actual monthly student loan payment, whether you are in repayment, deferment, or forbearance. If your loans are in forbearance and you are not making payments, some lenders will still estimate a payment based on your loan balance and count that estimated amount.
What if I am married — do we calculate one ratio or two?
For a joint mortgage process, lenders combine both incomes and both debts into a single ratio. If only one spouse is explore, only that person's income and debts count. If you are not married but explore together, each person's income and debts are calculated separately, and the lender uses the higher ratio.
Does my car insurance or health insurance count as debt?
No. Insurance premiums are not debt payments. The only exception is if your insurance is bundled into a loan payment — for example, if your car loan payment includes gap insurance or if your mortgage payment includes homeowners insurance.
Can I lower my ratio by not paying a debt?
No. Unpaid debts still count as obligations, and they damage your credit score. Lenders will see the unpaid debt on your credit report and will likely deny your process regardless of your ratio.
How often do lenders recalculate my ratio?
Lenders calculate your ratio when you explore for a loan. They pull recent statements and credit reports to get current numbers. If you explore again six months later after paying down debt, your ratio will be recalculated based on your new statements.