Student Loan Comparison Calculator

No. Federal Total Interest is calculated entirely from Loan Amount, Federal Interest Rate, Loan Term (Years), and Grace Period (Months) -- Private Interest Rate has no effect on it. The two loan calculations are independent of each other; only the Cheaper Option, Monthly Savings, and Total Savings outputs compare them side by side.

A higher interest rate always increases the interest portion of a standard amortized loan payment for the same principal and term, so Private Total Interest rises every time Private Interest Rate rises, holding Loan Amount and Loan Term (Years) constant. This holds true no matter how high or low the starting rate is.

Only subsidized federal loans avoid accruing interest during the grace period -- unsubsidized federal loans and virtually all private loans continue accruing interest while a borrower is in school or in the post-graduation grace window. This calculator adds that accrued interest onto the starting balance before repayment begins, which is the more conservative (and for most private and many federal loans, more accurate) assumption.

Not in a single run. Loan Term (Years) is applied to both the federal and the private loan, which isolates the rate difference but means the lower monthly payment is always also the lower Total Paid here. To weigh a 10-year federal standard plan against a longer private term, run the calculator once at each term and compare the Total Paid figures yourself — a longer term lowers the monthly payment while raising total interest.