There’s no set number. That’s because borrowing capacity differs from person to person, as well as lender to lender.
Lenders don’t give out car loans unless they’re confident they’ll be repaid. Each person is different, so the amount of money one person can successfully borrow will differ from another person’s number. Also, each lender uses its own formulas to calculate borrowing capacity – so Mr & Mrs Smith might find that while Lender X will give them a car loan for $20,000, Lender Y will offer only $18,000.