Most people want or need a cosigner because they can't qualify for the loan by themselves. Since most students (especially undergraduate students) do not have much credit history or income, it can be helpful to include a cosigner that does. It’s also common to include a cosigner as a way to reduce the interest rate on your loan.

Even though you may be able to qualify on your own, a cosigner with a high credit score and strong income can make you eligible for rates not available to you as a solo borrower.