What are your front-end and back-end debt-to-income ratios — and how do they compare to the thresholds lenders apply when evaluating a loan application?
This tool is for: Mortgage or loan applicants who want to know their DTI before submitting an application · Borrowers evaluating whether their current debt load leaves room for a new loan payment · Anyone comparing their debt profile against the 28/36 or 28/43 lender guidelines
- Your front-end DTI — the share of gross income consumed by housing costs alone
- Your back-end DTI — the share consumed by all recurring monthly debt obligations
- Your total monthly debt burden and the income remaining after all debt payments
- How your ratios compare to common lender acceptance thresholds
Formulas Used
Front-End DTI (Housing Ratio)
Front-End DTI = (Monthly Housing Payment / Gross Monthly Income) × 100
Where: Front-End DTI = Housing costs as a percentage of gross monthly income (%), Monthly Housing Payment = Principal, interest, taxes, insurance, and HOA (PITI) for homeowners; rent for renters (USD), Gross Monthly Income = Pre-tax monthly income from all sources (USD)
Source: Consumer Financial Protection Bureau — Debt-to-Income Ratio ✓ Verified
Back-End DTI (Total Debt Ratio)
Back-End DTI = (Monthly Housing Payment + All Other Monthly Debt Payments) / Gross Monthly Income × 100
Where: Back-End DTI = All recurring monthly debt obligations as a percentage of gross monthly income (%), Monthly Housing Payment = Housing cost component of total monthly debt (USD), All Other Monthly Debt Payments = Credit cards (minimum), auto loans, student loans, personal loans, child support, alimony (USD), Gross Monthly Income = Pre-tax monthly income from all sources (USD)
Source: Consumer Financial Protection Bureau — Debt-to-Income Ratio ✓ Verified
Key Insight
On a $6,000/month gross income with $1,500 in housing and $600 in other debts: front-end DTI is 25% (within the 28% conventional guideline) and back-end DTI is 35% (within the 36% conventional ceiling). Total monthly debt is $2,100, leaving $3,900 of gross income uncommitted to debt service. When back-end DTI approaches 43%, reducing one debt obligation — even a small one — can shift the calculation meaningfully.
Frequently Asked Questions
What is the difference between front-end and back-end DTI?
Front-end DTI (also called the housing ratio) measures only housing costs — principal, interest, taxes, insurance, and HOA — as a percentage of gross monthly income. Back-end DTI measures all recurring monthly debt payments, including housing, as a percentage of gross income. Lenders check both: front-end to assess the housing burden specifically, back-end to assess total debt load. The conventional guideline is front-end ≤ 28% and back-end ≤ 36%, though many programs allow higher ratios with compensating factors.
Does DTI use gross income or take-home pay?
DTI uses gross (pre-tax) income. Lenders apply DTI to gross income because taxes vary by filing status and deductions, and because gross income is the verifiable figure on pay stubs, W-2s, and tax returns. Using take-home pay would produce a higher DTI and is not how lenders underwrite. Enter your gross monthly income — your salary before taxes and withholding, not the amount deposited to your account.
What monthly obligations are included in the back-end DTI calculation?
Back-end DTI includes: housing payment (rent or PITI), minimum monthly payments on all credit cards, auto loan monthly payments, student loan monthly payments (including income-based repayment amounts), personal loan payments, child support or alimony obligations, and any other recurring monthly debt the lender can verify. It does not include utilities, groceries, subscriptions, insurance premiums (other than homeowners/mortgage insurance included in PITI), or discretionary spending. The key test is whether the obligation is a required minimum payment on a debt instrument.
About This Calculator
Sources:
- Consumer Financial Protection Bureau — What is a debt-to-income ratio? — Official CFPB definition and methodology for front-end and back-end DTI ratios and the 43% qualified-mortgage ceiling
- Consumer Financial Protection Bureau — Qualified Mortgage Rule — The 43% back-end DTI ceiling for qualified mortgages under Regulation Z and the ability-to-repay standard
Limitations:
- DTI is calculated using the gross income and debt figures entered — lenders may verify income differently (e.g., averaging two years of self-employment income) and may include or exclude certain obligations
- Front-end guideline of 28% and back-end guideline of 36% are conventional mortgage norms — FHA, VA, USDA, and jumbo loan programs use different thresholds
- Remaining income after debt is gross income minus debt only — taxes, utilities, and other living expenses are not deducted; actual discretionary income is lower
- Does not model how a proposed new loan payment would change either DTI ratio — use the loan-affordability-calculator to determine the maximum payment that fits within a target DTI
When to consult a professional: Before submitting a mortgage or large loan application, especially when back-end DTI exceeds 36%, when income is irregular or self-employment-based, or when considering strategies to reduce DTI before applying
This calculator computes front-end and back-end debt-to-income ratios using standard lender formulas and the gross monthly income and debt payments you enter. DTI thresholds vary by loan product, lender, and compensating factors. This tool does not constitute financial or mortgage advice and does not represent a pre-qualification or pre-approval.