- Loan balance
- The amount you currently owe, including any unpaid interest that has been added to principal. Use today’s payoff amount from your servicer rather than the amount originally borrowed, since interest that accrued during school or deferment may have increased it. The calculator repays this balance in full over the term you enter.
- Interest rate
- The annual percentage charged on the outstanding balance. Federal student loans carry fixed rates set each year for new loans; private loans may be fixed or variable. The calculator divides the rate by 12 and applies it to the remaining balance each month, so a higher rate raises both the payment and total interest.
- Repayment term
- The number of years over which the loan is scheduled to be fully repaid. The standard federal plan uses 10 years; income-driven plans can extend repayment to 20 to 25 years (per this calculator’s federal guidance). A longer term lowers the monthly payment but keeps the balance outstanding longer, so total interest rises.
- Monthly payment
- The fixed amount due each month that pays off the balance and interest by the end of the term. It is calculated with the standard amortization formula from the balance, rate and term. Paying more than this amount shortens the loan and reduces total interest, provided the servicer applies the extra to principal.
- Amortization
- Paying off a loan through regular, equal payments that cover both interest and principal. Early payments are mostly interest because the balance is at its highest; later payments are mostly principal. The repayment schedule this calculator produces shows that shift month by month until the balance reaches zero.
- Total interest
- The sum of all interest paid over the life of the loan, assuming every scheduled payment is made on time and nothing extra is paid. It is total repaid minus the starting balance. Rate and term drive it most; extending the term to lower the payment is the most common way it grows.
- Total repaid
- Everything you pay over the life of the loan: the monthly payment times the number of payments, which equals the balance plus total interest. Comparing this figure across different terms or rates is the simplest way to see the real cost of a lower monthly payment.
- Federal vs. private student loans
- Federal loans are made by the U.S. Department of Education and come with fixed rates, income-driven repayment options and possible forgiveness programs. Private loans come from banks and other lenders, with terms based on credit and fewer borrower protections. This calculator models a simple fixed-rate schedule, which fits either type only on a standard plan.
- Income-driven repayment
- Federal repayment plans that set the monthly payment as a share of your discretionary income rather than by the balance and rate. They can extend repayment well beyond the standard term, and any balance left at the end may be forgiven. This calculator does not model income-driven plans; check your servicer for those payment amounts.
