DTI Ratio for Auto Loans: What GM Financial Looks For

Updated: May 26, 2026

DTI vs PTI: Two Different Ratios

GM Financial uses two income ratios during underwriting — and it is important to know the difference:

PTI (Payment-to-Income): Your new car payment only, divided by gross monthly income. Measures whether you can afford this specific car payment.

DTI (Debt-to-Income): ALL monthly debt payments combined, divided by gross monthly income. Measures your total financial burden.

Both ratios matter. A good PTI with a high DTI will still raise flags.

How to Calculate Your DTI

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

Include in monthly debt payments:

Current car payment(s) — or the new payment if replacing
Rent or mortgage payment
Minimum credit card payments
Student loan payments
Personal loan payments
Child support or alimony obligations
Any other installment or revolving debt

Do NOT include:

Utilities (electric, gas, water)
Subscriptions (Netflix, phone)
Groceries, insurance, or living expenses
Savings contributions

Example:

Debt	Monthly Payment
Rent	$1,200
Student loan	$280
Credit card minimums	$120
New car payment (target)	$450
Total	$2,050

Monthly gross income: $5,800

DTI = $2,050 ÷ $5,800 = 35.3%

This would be within GM Financial’s preferred range.

GM Financial DTI Guidelines

DTI Range	Assessment	Typical Outcome
Under 35%	Excellent	Full program access at all credit tiers
35–40%	Good	Approved across most tiers
40–45%	Marginal	GM Financial’s approximate upper threshold
45–50%	High risk	Often denied; co-signer or higher down payment may help
Above 50%	Very high	Typically declined; address debts before applying

GM Financial’s published guideline is approximately 40–45% maximum DTI. Exact thresholds vary by credit tier, loan term, and vehicle type (new vs used). For DTI limits broken down by credit score tier, see GM Financial Credit Approval Tiers.

Higher credit scores can sometimes offset a higher DTI. A Tier 1 borrower (720+) at 43% DTI is more likely to be approved than a Tier 3 borrower (650) at the same DTI.

DTI vs PTI: What Matters More?

Both matter, but they measure different things:

PTI is checked first — it tells GM Financial whether this specific payment is affordable relative to income
DTI is the broader stress test — it tells them whether your total debt load leaves enough room to handle this new payment plus everything else

You can have a perfect PTI (8%) and still be denied if your DTI is 55% because of mortgage + student loans + existing car payments.

How to Lower Your DTI Before Applying

Fastest ways:

Pay off a small installment loan — eliminates that monthly payment entirely. Even paying off a $2,000 balance with 24 months remaining removes a fixed monthly obligation from your DTI calculation.
Pay down credit card balances — reduces minimum payment requirements, which count in DTI. A $4,000 balance at 2% minimum = $80/month off your DTI if zeroed out.
Increase your income — take on consistent additional income (a second job or documented freelance work) 2+ months before applying so it can be verified.
Reduce the car payment target — a lower-priced vehicle reduces the new payment in the DTI equation.

Does not help:

Closing credit card accounts (removes available credit but does not lower minimum payment DTI calculation for paid-off cards)
Paying extra on mortgage (does not reduce the monthly payment obligation)

Checking Your Numbers

Use the GM Income Calculator to calculate your verified monthly gross income, then manually calculate your DTI with the formula above. Know both your PTI and DTI before stepping into the dealership. If your income varies by period, see How to Calculate YTD Income for GM Financial for the correct annualization method.