Debt-to-income ratio: what it is and how to calculate it
Your debt-to-income ratio is one number that tells a lender how much room your budget has for another payment. It's simple math — and once you know it, you can see your own application the way an underwriter does.
Key takeaways
- Your DTI ratio is total monthly debt payments divided by gross monthly income, shown as a percentage.
- Front-end DTI counts only housing; back-end DTI counts all your debts.
- The CFPB suggests keeping back-end DTI at 36% or lower; 43% is the classic ceiling for a qualified mortgage.
- DTI doesn't affect your credit score, but lenders calculate it separately — so it can still make or break an approval.
What a debt-to-income ratio is
Your debt-to-income ratio — DTI for short — is the share of your gross monthly income that already goes toward debt. It answers one question a lender always asks: can you afford another payment?
A lower DTI means more of your income is free, so a new payment looks safer. A higher DTI means your budget is already stretched.
It's expressed as a percentage. A 30% DTI means roughly thirty cents of every pre-tax dollar is committed to debt before the new loan is even added.
The reason lenders lean on it is repayment risk. Two borrowers can earn the same income, but the one with less of it already spoken for has more cushion if money gets tight.
DTI is also one of the few numbers you can calculate yourself in a couple of minutes. Running it before you apply tells you, in advance, roughly how a lender will read your file.
Front-end vs. back-end DTI
Lenders actually look at two versions of the ratio, and the difference is just which debts you include.
- Front-end DTI counts only your housing payment — rent, or a mortgage with taxes and insurance — against your income.
- Back-end DTI counts all your recurring debt, including housing plus car loans, student loans, and credit-card minimums.
When someone says "your DTI," they almost always mean the back-end ratio. It's the broader, more telling number, and it's the one most lenders weigh most heavily.
Mortgage lenders often write the two together as a pair, like "28/36." The first figure is the front-end limit and the second is the back-end limit.
For most non-mortgage loans, only the back-end ratio matters. A personal or installment lender cares about your total obligations, not how they split between housing and everything else.
How to calculate your DTI
The formula has two ingredients and one step. Add up your monthly debt, divide by your gross monthly income, and turn it into a percentage.
DTI = (total monthly debt payments ÷ gross monthly income) × 100
"Gross" income means before taxes and deductions. Use the minimum payment for each debt, not what you'd like to pay or the full balance.
If your income varies — tips, freelance work, seasonal hours — lenders usually average it over the last 12 to 24 months. Use that same average so your own math matches theirs.
A worked example
Say the Reyes household earns $6,000 a month before taxes. Here's how their monthly debts add up, and how the ratio falls out.
| Monthly obligation | Amount | Running total |
|---|---|---|
| Rent | $1,500 | $1,500 |
| Auto loan | $380 | $1,880 |
| Student loan | $220 | $2,100 |
| Credit-card minimums | $100 | $2,200 |
| Total monthly debt | $2,200 | — |
Back-end DTI is $2,200 ÷ $6,000 = 0.367, or about 37%. Front-end DTI counts only the $1,500 rent: $1,500 ÷ $6,000 = 25%.
At 37% back-end, the Reyes household sits just above the 36% comfort zone but well under the 43% mortgage ceiling — a reasonable spot for most lenders.
What counts as debt — and what doesn't
DTI only counts recurring debt obligations, not every dollar you spend. Knowing the line saves you from over- or under-counting.
Counts toward DTI:
- Rent or mortgage (with property taxes and insurance)
- Auto loans and leases
- Student loans
- Personal and installment loans
- Minimum credit-card payments
- Court-ordered payments like child support or alimony
Usually doesn't count:
- Utilities, phone, and internet
- Groceries and gas
- Health insurance and most other insurance
- Streaming and other subscriptions
Want a fuller picture of where every dollar goes? It helps to build a budget first, then pull the debt lines out of it for your DTI.
What's a good DTI ratio?
There's no single passing grade, but there are clear guideposts. The Consumer Financial Protection Bureau suggests keeping your back-end DTI at 36% or lower, including housing.
Roughly speaking, lenders read the ranges like this:
- Under 36% — comfortable; most lenders see plenty of room.
- 36%–43% — workable, especially with strong credit; many programs still approve.
- Above 43% — tighter; you'll need compensating factors, and some loans are off the table.
The CFPB also notes that 43% is generally the highest DTI you can have and still land a qualified mortgage under the long-standing benchmark.
DTI thresholds by loan type
Different products draw the line in different places. The table below shows typical preferred and maximum back-end DTI by loan type, using current industry and agency guidance.
| Loan type | Preferred DTI | Max DTI (with factors) |
|---|---|---|
| Conventional mortgage (Fannie Mae) | ≤ 36% | ~50% |
| FHA mortgage | ~43% | ~56.9% |
| Personal / installment loan | ≤ 36% | ~43–45% |
| Auto loan | ≤ 36% | ~45–50% |
Two anchors are worth remembering. The 36% guideline is the broad comfort target, and the 43% qualified-mortgage rule is the historical ceiling for most home loans.
Higher maximums exist, but they aren't automatic. Reaching FHA's upper band or Fannie Mae's 50% generally takes a higher credit score, cash reserves, or an "approve" from the lender's automated underwriting system.
It's also worth knowing the 43% mortgage ceiling has shifted. The CFPB moved its General Qualified Mortgage standard toward a price-based test, so a loan can now qualify above 43% if its rate stays within a set band — but 43% remains the figure most of the industry still quotes.
How lenders use your DTI
DTI is a core part of underwriting — the process of deciding whether to lend and on what terms. It sits alongside your credit score and income as one of the big three.
Your credit score shows how you've handled debt; your DTI shows how much room you have for more. A great score with a stretched DTI can still draw a decline.
That's because the two measure different things. A score looks backward at your repayment history, while DTI looks forward at whether your budget can absorb the new payment you're asking for.
DTI also shapes the terms you're offered, not just the yes-or-no. A lower ratio can mean a better rate, which feeds directly into how lenders price your loan.
How to lower your DTI
Because DTI is a ratio, you can improve it from either side: shrink the debt on top, or grow the income on the bottom.
- Pay down balances to reduce the monthly minimums that feed the calculation.
- Avoid new debt in the months before you apply — a new card or car payment raises the ratio instantly.
- Raise income where you can, through a raise, a side income, or documenting all eligible earnings.
- Consolidate several payments into one. Rolling balances into a debt consolidation loan can lower your combined monthly obligation.
Predictability helps too. Replacing a revolving minimum with a fixed monthly payment makes your DTI easier to plan around, because the number doesn't drift month to month.
Small moves compound. Trimming even one payment can nudge you from the 36%–43% band into the comfortable zone before you apply.
Timing matters as much as the moves themselves. Lenders pull your DTI on the day you apply, so the cleanup is most valuable in the weeks just before — not after.
One caution: don't close old credit cards to "remove" debt. A card with a zero balance adds nothing to your DTI, and closing it can hurt your credit score instead.
Frequently asked questions
What is a debt-to-income ratio?
It's the share of your gross monthly income that goes toward minimum debt payments. Divide total monthly debt by gross monthly income, then multiply by 100 to get the percentage.
What is a good debt-to-income ratio?
The CFPB suggests keeping back-end DTI at 36% or lower, including housing. Many lenders treat 36% as comfortable and 43% as the upper edge for a qualified mortgage, though some programs allow more.
How do I calculate my DTI ratio?
Add up your monthly minimum payments — rent or mortgage, car, student loans, credit-card minimums, and other loans — then divide by your gross monthly income and multiply by 100.
What's the difference between front-end and back-end DTI?
Front-end DTI counts only housing costs against income. Back-end DTI counts all recurring debt, including housing. The back-end ratio is the one most lenders weigh most heavily.
What counts as debt in a DTI calculation?
Rent or mortgage, auto loans, student loans, personal and installment loans, minimum credit-card payments, and court-ordered support. It usually excludes utilities, groceries, insurance, and taxes.
Does my DTI affect my credit score?
No — DTI isn't part of your credit score because the bureaus don't see your income. But lenders calculate it during underwriting, so a high DTI can still cause a denial even with a strong score.
How can I lower my debt-to-income ratio?
Pay down balances to cut minimums, avoid new debt before applying, and raise income where you can. Consolidating several payments into one fixed loan can also reduce your total monthly obligation.
Sources
- Consumer Financial Protection Bureau — "What is a debt-to-income ratio?" (36% guideline; 43% qualified-mortgage benchmark). consumerfinance.gov.
- Consumer Financial Protection Bureau — Qualified Mortgage definition under the Truth in Lending Act (Regulation Z). CFPB General QM rule.
- Fannie Mae — Selling Guide B3-6-02, Debt-to-Income Ratios (DU maximum of 50%). selling-guide.fanniemae.com.
- FHA debt-ratio guidance — standard 31% front-end / 43% back-end, with higher limits via automated underwriting. fhahandbook.com.
- Examples are illustrative; actual limits vary by lender, program, and your credit profile.