Glossary

Payment-to-Income Ratio

Written by JaredLast reviewed 2026-08-25

What is payment-to-income ratio (PTI) in auto lending?

Payment-to-income ratio (PTI) is the monthly payment on a vehicle loan or lease divided by the borrower's gross monthly income, expressed as a percentage. It's one of the inputs auto lenders use during underwriting to gauge whether a proposed payment fits comfortably within what a borrower earns before taxes. PTI doesn't appear in the Bankruptcy Code, Regulation Z, or the Fair Credit Reporting Act — it's industry underwriting practice, developed and applied lender by lender, not a term with a statutory definition or a regulator-set standard.

The closely related, broader concept is debt-to-income ratio (DTI), which the Consumer Financial Protection Bureau defines as "all your monthly debt payments divided by your gross monthly income." PTI applies that same division to a single obligation — the vehicle payment — rather than to every debt a borrower carries.

How do you calculate PTI on a car loan?

The formula is monthly payment divided by gross monthly income, converted to a percentage. Lenders take the payment shown on the proposed retail installment contract — principal, interest, and anything rolled into that payment — and divide it by the gross monthly income figure the application uses.

The payments below are real Q1 2026 market averages from Experian; the income figures are hypothetical, chosen only to show how the same payment produces a different PTI depending on income:

What counts as gross monthly income?

Gross monthly income is earnings before taxes and other deductions, from every income source a borrower can document — the same base the CFPB uses to define DTI generally. Wages, self-employment income, Social Security, disability, and alimony can all count, depending on the lender's documentation requirements.

How that income gets verified varies by income type and by lender. W-2 wages are typically confirmed through recent pay stubs; self-employment or gig income, which doesn't come with a pay stub, is sometimes verified instead through bank statements or tax returns. No published standard sets which documents a lender must accept — that's set by each lender's own underwriting policy.

Why do lenders care about PTI instead of relying on credit score alone?

Because payment burden predicts default risk in a way a credit score doesn't fully capture on its own. A Federal Reserve Board FEDS Note, published September 26, 2024 by Robert Adams, Vitaly Bord, and Haja Sannoh, found that each 1 percentage point rise in a borrower's required monthly payment correlated with more than a 2.9 basis point rise in the likelihood of delinquency. The same note documented average required auto payments rising from about $470 in January 2020 to about $600 by January 2023 — an increase the authors attribute to larger loan amounts as car prices surged, not to rate increases, writing that higher interest rates "do not appear to explain the higher monthly payments" — and estimated that payment growth explained roughly 40% of the rise in auto loan delinquency over that period.

Two borrowers with identical credit scores can carry very different payment burdens depending on income, loan size, and term length. PTI is one way lenders capture that difference instead of pricing risk on credit score alone.

Is there a maximum PTI that auto lenders publish?

No. No regulator, credit bureau, or lender network publishes a maximum PTI for auto loans. Specific cap figures circulate across lending forums and aggregator content, but none trace to a primary source — not the CFPB, not the Federal Reserve, not Experian, not myFICO. That absence has a structural reason: the federal ability-to-repay rule that does require an income-based test, in Regulation Z at 12 CFR § 1026.43, applies only to a "covered transaction" secured by a dwelling under its own definition in § 1026.43(b)(1). An auto loan isn't secured by a dwelling, so that rule — and the income test it requires — never reaches vehicle financing. Nothing has filled that gap with a published national number for cars.

Individual lenders set their own internal PTI guidelines as part of proprietary underwriting criteria, and those guidelines aren't uniform or publicly disclosed the way an APR table is. A borrower who wants to know where a specific application stands should ask that lender directly rather than rely on a percentage found online. This is the same pattern documented in why the "30 to 45 day" Chapter 13 timeline answer is wrong — a specific number repeats across the bankruptcy-auto niche without any of the sites publishing it tracing back to where it came from.

What other factors do lenders weigh alongside PTI?

PTI is one input among several, not a single gate an application passes or fails.

See auto loan APR after bankruptcy, by credit tier for how credit tier specifically prices a loan once these factors are weighed.

Does a bankruptcy filing change how PTI is calculated?

No — the formula itself stays the same; a bankruptcy filing doesn't add or remove a step in dividing payment by income. What can change is what else that income is already committed to. In an active Chapter 13 case, 11 U.S.C. § 1322(a)(1) requires the debtor to submit future income to the trustee's "supervision and control" to the extent necessary to execute the plan. Because gross income is measured before debt payments are subtracted, a confirmed plan payment doesn't reduce the income figure a PTI calculation divides by — but that income isn't available in practice to support a new car payment stacked on top of it, a separate constraint from the ratio math itself.

Whether a Chapter 13 trustee will approve new debt at all is a different question from PTI, and it runs through the trustee-approval process described in motion to incur debt, which varies by district; see buying a car during an open Chapter 13 case for how that process works. A Chapter 7 filer has no ongoing plan payment competing with a new car payment, so PTI works the same way it would for any other borrower — though credit tier following the case, not PTI itself, is typically what shapes the rate offered.

This is general information about how lenders calculate and use payment-to-income ratio, not a promise of approval or any specific lender's underwriting criteria. Underwriting guidelines vary by lender and generally aren't disclosed publicly.