How to Calculate Your Debt-to-Income Ratio (DTI) Step-by-Step

Debt can be useful when it helps you buy a home, finance a business, pay for education or manage a major expense. The problem begins when too much of your income is already committed to monthly repayments.

One of the simplest ways to measure that pressure is the debt-to-income ratio (DTI).

DTI compares your monthly debt obligations with your gross monthly income. Banks and other lenders use it to assess whether a borrower has enough income to manage existing obligations while taking on additional debt. It can also be useful for individuals who simply want a clearer picture of their financial position.

The calculation is straightforward, but getting the details right matters. Here’s how to calculate your DTI correctly and understand what the result means.

What Is a Debt-to-Income Ratio?

Your debt-to-income ratio is the percentage of your gross monthly income that goes toward monthly debt payments.

The basic formula is:

DTI = Total Monthly Debt Payments ÷ Gross Monthly Income × 100

For example, if your qualifying monthly debt payments are $1,800 and your gross monthly income is $6,000:

$1,800 ÷ $6,000 × 100 = 30%

Your DTI is therefore 30%.

Fannie Mae describes DTI as the relationship between total monthly obligations and the monthly income used to qualify for a loan. Experian similarly defines DTI as total monthly debt payments divided by gross monthly income.

Step 1: Calculate Your Gross Monthly Income

The first number you need is your gross monthly income.

Gross income is generally the amount you earn before income taxes, retirement contributions and other deductions are taken out.

If you earn $84,000 a year:

$84,000 ÷ 12 = $7,000

Your gross monthly income is $7,000.

If you’re paid weekly, biweekly or irregularly, don’t simply use one month’s payslip. Convert your income into a reliable monthly figure.

For example, someone earning $1,500 every two weeks receives 26 payments in a typical year:

$1,500 × 26 = $39,000 annually

$39,000 ÷ 12 = $3,250 average monthly income

Income rules can become more complicated when earnings come from self-employment, commissions, bonuses, rental properties or multiple sources. A lender may have specific requirements for determining what income is stable and eligible for loan qualification.

Step 2: List Your Monthly Debt Payments

Next, write down your recurring monthly debt obligations.

Depending on the lender and type of loan, these can include:

Mortgage or housing payments

Auto loans

Student loans

Personal loans

Credit card payments

Other installment loans

Lease payments

Certain alimony or child-support obligations

Fannie Mae’s current mortgage underwriting guidance includes several of these obligations when determining total monthly debt.

The important point is that DTI focuses on monthly payment obligations, not simply how much you owe in total.

For example, owing $25,000 on a car does not mean you enter $25,000 into the calculation. You would generally use the relevant monthly payment.

Step 3: Know What Usually Isn’t Included

Not every expense that leaves your bank account is considered debt.

Fannie Mae’s consumer guidance, for example, says monthly debt calculations do not include expenses such as utilities, cell phone bills or internet service.

That means a monthly budget might look like this:

Rent: $1,500

Car loan: $400

Credit cards: $200

Utilities: $250

Groceries: $500

Only the expenses that qualify as debt or housing obligations under the applicable calculation would generally be included. Utilities and groceries are ordinary living expenses, not debt payments.

This distinction is important because DTI is a lending measurement, not a complete household affordability calculation.

Someone can have a relatively low DTI and still struggle financially because of expensive childcare, transportation, insurance, food or other living costs.

Step 4: Add Your Monthly Debt Payments

Now add the monthly payments that belong in your calculation.

Suppose your finances look like this:

Mortgage: $1,500

Car loan: $450

Student loan: $300

Credit card minimum payments: $150

Personal loan: $200

Your total monthly debt is:

$1,500 + $450 + $300 + $150 + $200 = $2,600

Your total monthly debt obligation is therefore $2,600.

For revolving credit such as credit cards, the required monthly payment is generally what matters for the basic calculation. However, lender-specific underwriting rules can differ. Fannie Mae, for example, has specific requirements for how revolving debt is treated when the reported payment is unavailable.

SUGGESTED ARTICLES:

Step 5: Divide Debt by Gross Monthly Income

Now apply the formula.

Assume your gross monthly income is $7,000 and your monthly debt payments are $2,600.

$2,600 ÷ $7,000 = 0.3714

Multiply by 100:

0.3714 × 100 = 37.14%

Your DTI is approximately 37.1%.

In simple terms, about 37% of your gross monthly income is committed to the debt obligations included in the calculation.

A Complete DTI Example

Consider a borrower earning $90,000 annually.

First, calculate gross monthly income:

$90,000 ÷ 12 = $7,500

Now assume the borrower has:

Mortgage: $1,700

Car loan: $450

Student loan: $350

Credit card payments: $200

Personal loan: $300

Total monthly debt:

$1,700 + $450 + $350 + $200 + $300 = $3,000

Now calculate DTI:

$3,000 ÷ $7,500 × 100 = 40%

The borrower’s DTI is 40%.

If the borrower is considering another loan with a $400 monthly payment, the new debt obligation would be $3,400.

The new DTI would be:

$3,400 ÷ $7,500 × 100 = 45.3%

The proposed loan would therefore increase the borrower’s DTI from 40% to approximately 45.3%.

This is one of the most useful reasons to calculate DTI before borrowing. It lets you see how a new monthly payment could change your overall debt burden.

Front-End DTI vs. Back-End DTI

You may encounter two DTI measurements, particularly when researching mortgages.

Front-end DTI focuses on housing-related costs compared with gross income.

Back-end DTI looks at housing costs together with other qualifying monthly debt obligations.

Experian describes front-end DTI as housing costs relative to gross income, while back-end DTI includes housing and other debts such as credit cards, auto loans and student loans.

For example, if your gross monthly income is $7,000 and your qualifying housing expense is $2,100:

$2,100 ÷ $7,000 × 100 = 30%

Your front-end DTI would be 30%.

If you also have $700 in other qualifying monthly debt:

($2,100 + $700) ÷ $7,000 × 100 = 40%

Your back-end DTI would be 40%.

The exact treatment of housing expenses and other obligations depends on the lender and loan program.

What Is a Good DTI Ratio?

There isn’t one DTI percentage that guarantees approval for every type of loan.

Lenders use different underwriting standards, and the acceptable ratio can depend on the loan product, credit profile, income, assets and other factors.

As one example, Fannie Mae’s current guidance sets a maximum total DTI of 36% for manually underwritten loans, with the possibility of reaching 45% when specified credit-score and reserve requirements are met. Its automated underwriting system can permit higher ratios in qualifying cases.

Experian also notes that lenders have different requirements and that a lower DTI is generally viewed more favorably.

So rather than treating a particular percentage as a universal pass-or-fail line, think of DTI as a measure of how heavily your income is already committed to debt.

What a High DTI Can Mean

A high DTI means a larger share of your income is already going toward debt payments.

For example, a borrower earning $5,000 per month with $1,000 in monthly debt has a DTI of 20%.

Another borrower earning the same $5,000 but paying $2,500 toward debt has a DTI of 50%.

The second borrower has significantly less room to absorb another monthly payment.

A high DTI can make it more difficult to qualify for certain loans and may affect the terms available to you. Lenders may also look at your credit history, income stability, assets and other factors rather than relying on DTI alone.

How to Lower Your Debt-to-Income Ratio

There are two basic ways to improve DTI: reduce qualifying monthly debt or increase qualifying income.

Paying down debt can reduce your monthly obligations, particularly when you eliminate a loan or reduce revolving debt enough to lower the required payment.

Increasing income can also improve the ratio.

For example, suppose your monthly debt payments are $2,400.

At $6,000 monthly income:

$2,400 ÷ $6,000 × 100 = 40%

If your qualifying income increases to $7,000:

$2,400 ÷ $7,000 × 100 = 34.3%

The debt stayed exactly the same, but your DTI improved because your income increased.

Experian identifies paying down debt, increasing income, avoiding new debt and, where appropriate, consolidation or refinancing as potential ways to lower DTI.

The goal, however, should be improving your actual financial position rather than simply finding ways to make a ratio appear lower.

DTI Does Not Tell the Whole Financial Story

A DTI of 30% does not necessarily mean someone is financially comfortable.

Imagine two people who both have a 30% DTI. One has substantial savings, low living costs and stable employment. The other has no emergency savings, expensive childcare and unpredictable income.

Their DTI is identical, but their financial situations are very different.

This is why DTI should be considered alongside emergency savings, cash flow, credit history, income stability and overall monthly expenses.

DTI also isn’t the same thing as a credit score. A credit score reflects information in your credit history, while DTI measures the relationship between debt payments and income.

Calculate Your DTI Before Applying for New Debt

You don’t have to wait until a lender asks for your DTI.

Calculate it before applying for a mortgage, auto loan, personal loan or another major credit product.

Start with your gross monthly income. List your qualifying monthly debt payments. Add them together, divide the total debt by your gross income and multiply by 100.

Then calculate the ratio again using the proposed payment for the new loan.

That second calculation can be more useful than simply asking whether you qualify. It shows how the new debt could change your financial commitments.

The Bottom Line

The debt-to-income ratio is one of the simplest ways to understand how much of your income is already committed to debt.

The formula is simple:

DTI = Total Monthly Debt Payments ÷ Gross Monthly Income × 100

But the quality of the result depends on using the correct income figure and including the appropriate monthly obligations.

A lower DTI generally gives you more financial breathing room and can strengthen your position when seeking new credit. A higher DTI signals that a larger portion of your income is already committed to debt.

Most importantly, don’t use DTI as your only measure of affordability. Before taking on new debt, look at your complete monthly budget, emergency savings and ability to handle the payment if your circumstances change.

Author

Onyeka M. Kimekwu

Financial Researcher & Editor

at Makon Financials with over four years of experience specialising in financial markets, economic developments, and corporate finance across Africa, the Middle East, and global markets. His work focuses on analyzing financial data, examining market developments, and translating complex economic information into clear, accurate, and insightful reporting.