How Debt-to-Income Ratio Works

 

Your debt-to-income ratio, or DTI, is one of the main numbers a mortgage lender uses to judge whether you can handle a new monthly payment. It is simple to calculate, but there is a lot of confusion about which debts count and what counts as "too high." This guide explains how DTI works and how to use it in your own planning.

On this page

1. What debt-to-income ratio is
2. How to calculate DTI
3. Front-end vs. back-end ratios
4. What usually counts and what usually doesn't
5. Is there a maximum DTI?
6. Ways to lower your DTI
7. What DTI doesn't tell you
8. Key takeaways

What debt-to-income ratio is

The Consumer Financial Protection Bureau defines your debt-to-income ratio as all your monthly debt payments divided by your gross monthly income. Gross income is your income before taxes and other deductions are taken out. Lenders use DTI to estimate how much room your budget has for a new loan payment.

DTI is not the only factor in a mortgage decision. Lenders also consider your credit history, savings and assets, employment and income stability, the loan amount compared with the home's value, and the type of loan. Still, DTI often limits how large a payment, and therefore how large a loan, a lender will approve.

How to calculate DTI

The basic calculation has three steps:

1. Add up your recurring monthly debt payments, including the proposed new housing payment if you are applying for a mortgage.
2. Figure out your gross monthly income. For a salary, divide your annual pay by 12.
3. Divide total monthly debts by gross monthly income and multiply by 100 to get a percentage.

Example: A hypothetical household's DTI

A household earns $90,000 a year before taxes, which is $7,500 per month. Its current monthly debt payments are:

• Car loan: $400
• Student loan: $250
• Credit card minimum payment: $75

That's $725 per month. The household is considering a home with an estimated housing payment of $2,300 per month, including principal, interest, property taxes, and insurance.

• Housing-only ratio: $2,300 ÷ $7,500 ≈ 30.7%
• Total DTI: ($2,300 + $725) ÷ $7,500 = $3,025 ÷ $7,500 ≈ 40.3%

Our debt-to-income ratio calculator runs these numbers for you. If you don't know your future housing payment yet, estimate it first with the mortgage payment calculator and add estimated taxes and insurance, as described in how mortgage payments are calculated.

Front-end vs. back-end ratios

You will often see two versions of DTI:

• Front-end ratio (sometimes called the housing ratio): only your housing payment divided by gross monthly income. In the example above, that is about 30.7%.
• Back-end ratio (total DTI): housing plus all other recurring debts divided by gross monthly income. In the example, that is about 40.3%.

When people say "DTI" without further detail, they usually mean the back-end ratio. Individual lenders and loan programs decide which ratios they look at and how they weigh them.

What usually counts and what usually doesn't

Exact rules depend on the lender and loan program, but this is a general guide to what is typically included.

Monthly obligations commonly included in, or left out of, DTI (general guide; rules vary)

Usually included	Usually not included
Proposed mortgage payment, including taxes, insurance, mortgage insurance, and HOA dues	Utilities such as electricity, water, and internet
Auto loan or lease payments	Groceries, gas, and other everyday spending
Student loan payments	Health and car insurance premiums
Minimum required credit card payments	Phone bills and subscriptions
Personal loans and other installment debts	Retirement contributions and savings
Court-ordered payments such as child support or alimony	Income taxes withheld from your pay

Note that lenders use the minimum required payment on revolving accounts like credit cards, not the amount you happen to pay. The way they treat deferred student loans, co-signed debts, or debts close to payoff varies, so ask each lender how it handles your situation.

Is there a maximum DTI?

There is no single DTI limit that applies to every mortgage. The CFPB notes that different loan products and lenders have different DTI limits. Many lenders also allow higher ratios when other parts of an application are strong, or set lower ratios when they aren't.

Where the "43%" figure comes from

You may still see 43% described as the maximum DTI. That number comes from the CFPB's original Qualified Mortgage (QM) rules, which generally required a DTI of 43% or less for a loan to be a "General QM." In December 2020, the CFPB issued a final rule that removed the 43% limit from the General QM definition and replaced it with price-based thresholds. Under that rule, QM status depends on how the loan's annual percentage rate (APR) compares with a benchmark average rate for similar loans. Compliance became mandatory on July 1, 2021.

That change didn't mean DTI stopped mattering. The CFPB explains that, for a Qualified Mortgage, lenders must still consider your DTI or residual income along with your income, assets, and debts. In practice, each lender and loan program applies its own DTI standards.

Example: Working backward from a hypothetical limit

Suppose a lender's limit for a particular application were a hypothetical 43%. For the household above earning $7,500 a month, total debts could be up to $7,500 × 0.43 = $3,225. Subtracting the existing $725 in debts leaves about $2,500 per month for the full housing payment. With a different limit, the result changes. Qualifying for a payment doesn't mean the payment fits comfortably in your budget.

Ways to lower your DTI

DTI can change in two ways: lower monthly debt payments or higher documented income. Common approaches include:

• Paying off small balances. Eliminating a debt removes its monthly payment entirely. In the example, paying off the $400 car loan would drop total DTI from about 40.3% to 35.0%.
• Avoiding new debt before and during the mortgage process. A new car loan or store card can raise your DTI and change your approval. Many lenders check your credit again shortly before closing.
• Choosing a less expensive home or a larger down payment. Both reduce the proposed housing payment.
• Comparing loan types and terms. Different terms and loan structures produce different payments. Adjustable-rate loans may start lower but can rise later. See fixed-rate vs. adjustable-rate mortgages before choosing on payment alone.
• Documenting all qualifying income. Income that is stable and can be documented, such as consistent overtime or a second job with a track record, may count. Lenders decide what qualifies.

Paying down a credit card balance can lower its minimum payment, but it may not remove the payment entirely. Ask your lender how a payoff or paydown would be reflected before you move large amounts of savings, because you also need cash for the down payment, closing costs, and reserves.

What DTI doesn't tell you

DTI is a lender's screening tool, not a full picture of affordability. It is based on gross income, so it ignores taxes, retirement contributions, and benefit deductions. It also leaves out childcare, commuting, healthcare, home maintenance, and saving for emergencies. Two households with the same DTI can have very different amounts of money left at the end of the month.

For your own planning, start with your take-home pay and actual monthly spending, then decide what housing payment you are comfortable with. Our mortgage affordability calculator can help you test different price ranges.

Key takeaways

• DTI = total monthly debt payments ÷ gross monthly income.
• The front-end ratio covers housing only. The back-end ratio includes all recurring debts.
• There is no single universal DTI limit. Lenders and loan programs set their own standards.
• The 43% General QM DTI limit was replaced by price-based thresholds under a CFPB rule that became mandatory in 2021, but lenders must still consider DTI or residual income.
• A ratio you qualify for may still be uncomfortable. Check it against your real budget.

Enter your income and monthly debts to see your front-end and back-end ratios.

Open the debt-to-income ratio calculator

Getting ready to buy? Work through our first-time homebuyer's mortgage checklist or browse more home buying guides.

Sources

1. What is a debt-to-income ratio? — Consumer Financial Protection Bureau
2. What is a Qualified Mortgage? — Consumer Financial Protection Bureau
3. Consumer Financial Protection Bureau Issues Two Final Rules to Promote Access to Responsible, Affordable Mortgage Credit — Consumer Financial Protection Bureau (December 10, 2020)

This article is for general educational purposes only and is not financial, legal, or tax advice. ClearPath Guides is not a lender, mortgage broker, or licensed adviser. Lender and program requirements vary and change over time. Read our full disclaimer.