Debt-to-income ratio for mortgage: What it means and how to calculate it

Your debt-to-income ratio—the percentage of your monthly income that goes toward debt payments each month—is one of the first numbers that comes up in the mortgage (or HELOC) application process. DTI is not a measure of how timely your debt payments are. This number simply reflects how much of your monthly income is already committed to debt payments. Understanding your DTI may help you better prepare for the application process.

What is a debt-to-income ratio (DTI) for a mortgage?

Debt-to-income (DTI) ratio is an expression of the percentage of your monthly income that goes toward monthly debt payments. Lenders use it to get a sense of your financial capacity.

Lenders may consider two versions.

• Front-end DTI covers only your housing costs: your mortgage principal and interest, property taxes, homeowner's insurance, and any HOA fees or mortgage insurance.

• Back-end DTI is a broader number. Back-end DTI includes your housing costs plus all other monthly debt obligations, like car loans, student loans, credit card minimums, and personal loans.

Lenders may calculate DTI slightly differently depending on the loan type and documentation, so the number your lender uses could vary from your own estimate.

What debt-to-income ratio is needed for a mortgage?

Requirements vary by lender and loan type, so there is no universal DTI for every mortgage. One common guideline you may come across is the 28/36 rule: front-end DTI at or below 28%, and back-end DTI at or below 36%. The 28/36 rule is a guideline, not a guarantee of approval or denial.

DTI requirements vary by loan program and lender. A back-end DTI below 36% is a widely cited benchmark, though many programs accept higher ratios, depending on your overall application. Your credit score, down payment, assets, and overall financial picture all factor into a lender's decision alongside DTI. Talk to a loan consultant to understand what a specific lender may look for.

What DTI is too high for a mortgage?

A higher DTI means less room in your monthly budget once a housing payment is added. There is no universal cutoff, though individual lenders typically establish a limit they're comfortable with.

How to calculate debt-to-income ratio for a mortgage

The formula involves a few steps. You can run these numbers yourself in a few minutes, or use a debt-to-income ratio calculator to make it easier.

To calculate manually:

1. Add up your required minimum payments—credits, auto loans, student loans, personal loans, child support, and any other recurring obligations.

2. Add your estimated housing payment, which could be your rent or mortgage payment, plus property taxes, homeowner's insurance, HOA fees, and mortgage insurance if applicable. 

3. Divide that total by your gross monthly income.

4. Multiply by 100 to get a percentage.

Example: Monthly debt payments of $500, plus an estimated housing payment of $1,500, divided by gross monthly income of $7,000, multiplied by 100 equals a back-end DTI of about 28.6%.

Your lender verifies income and debts independently, and their calculation may differ from your own estimate. Actual DTI requirements and calculations depend on the specific loan program and lender underwriting guidelines

What counts and doesn't count in DTI 

Lender requirements vary; always consult with your loan officer for a definitive list of included obligations. Your lender confirms exactly what they include in DTI based on documentation. These general guidelines apply in most cases.

Typically counts:

• Credit card minimum payments

• Auto loan payments

• Student loan payments

• Personal loan payments

• Alimony or child support obligations

Typically doesn't count:

• Groceries and utilities

• Streaming subscriptions

• Home maintenance

• Insurance premiums other than those included in a housing payment

How to lower your debt-to-income ratio before applying

If your DTI is higher than you'd like, a few approaches may help:

• Pay down balances on revolving accounts, like credit cards, to reduce your minimum payment requirements.

• Increase documented income if you have freelance work, ask for a raise, or bring in other verifiable earnings.

• Adjust your home budget by considering a lower purchase price or a larger down payment.

• Restructure existing debt if doing so results in a lower documented monthly payment obligation.

If you're carrying a significant amount of unsecured debt, you might consider debt consolidation before you apply.

Read more: How to pay off credit card debt