Interest Rates

The interest rate on a consolidation loan is the weighted average of the interest rates on the loans being consolidated, rounded up to the nearest 1/8 of a percent and capped at 8.25%.
For example, suppose a student has just unsubsidized Stafford Loans originated on or after July 1, 2006. These loans have a fixed interest rate of 6.8%. When they are consolidated by themselves, the consolidation loan will have an interest rate of 6 and 7/8ths of a percent, or 6.875%. So the interest rate increases only slightly.
If the borrower has a mix of loans with different interest rates, the weighted average will be somewhere in between. For example, if the borrower has $5,000 of Perkins Loans (at 5.0%) and $10,000 of unsubsidized Stafford Loans (at 6.8%), the weighted average is
$5,000 * 5.0% + $10,000 * 6.8%
------------------------------ = 6.2%
$5,000 + $10,000