Consolidation combines multiple federal student loans into a single loan with one monthly payment; this payment can be significantly lower than the payment required otherwise.
A Consolidation Loan pays off the existing federal student loans; the borrower then repays the Consolidation Loan. Most federal student loans are eligible for consolidation, including:
Subsidized & Unsubsidized Federal Direct and Federal Stafford Loans
Federal Graduate PLUS loans
Federal Perkins Loans
Health Professions Student Loans
Federal Parent PLUS loans.
Consolidation Loans are available through the FFEL (Federal Family Education Loan) program and the Federal Direct Loan Program. Both allow the borrower to combine different types and amounts of federal student loans to simplify repayment.
Remember, once made, consolidation loans can't be unmade because the loans that were consolidated have been paid off and no longer exist. So, make sure to research your consolidation options before you apply.