The interest rates for federal student loan consolidations are based on the weighted average of student loan interest rates. Federal Stafford loans disbursed between July 1, 2006 and June 30, 2008 have an interest rate of 6.8%*. Stafford loans disbursed after July 1, 2008 have a rate of 6.0%.
Federal student loans will have different rates depending on type and disbursement dates. For example, rates for Stafford loan disbursed before July 1, 2006 will remain variable until consolidated. Visit StaffordLoan.com or ParentPLUSLoan.com for more details on federal student loan interest rates.
Source