Binding promise from a lender that a specified amount of loan or line of credit will be made available to the named borrower at a certain interest rate, during a certain period and, usually, for a certain purpose. The commitment letter often also specifies the terms and requirements under which the loan will be advanced. Lenders charge a commitment fee (ranging generally from 0.5 percent to 2.5 percent of the loan amount) for giving a written commitment.