Student Loan Calculator: Calculation and Examples
Estimate fixed monthly student loan payments, total interest, and the remaining balance over time.
Understanding the calculation
Models a standard fixed-rate repayment schedule. Income-driven repayment, forgiveness, deferment, subsidized interest, and capitalization are not included.
Student Loan formula
M = P × r ÷ [1 − (1 + r)⁻ⁿ], where P is principal, r is annual interest ÷ 1,200, and n is the number of months. At 0%, M = P ÷ n.
Worked example
A $24,000 loan over 60 months at 0% has a $400 monthly payment. At a positive rate, interest increases the required installment.
Assumptions and interpretation
Repayment estimates use fixed interest and equal monthly periods. No fees, rate changes, new borrowing, missed payments, or penalties are added. Interest accrues on the remaining balance, and the last modeled payment is capped at the amount owed.
Displayed amounts are rounded; intermediate calculations use unrounded values. Compare the result with the terms and payment schedule in your agreement. For background on the calculation, read the CFPB explanation of principal and interest payments.
Frequently asked questions
What happens when the interest rate is zero?
No interest is added. Payments reduce principal directly, so a fixed term divides principal equally and a fixed payment determines how many months repayment takes.
Why might the actual result differ?
Payment timing, daily interest accrual, contract rounding, fees, and changing rates can differ from the monthly estimate. Check the lender or issuer’s agreement for the method used.
What inputs should I enter?
Use amounts and rates from the relevant agreement, with time periods matching the labels. Enter zero for an optional amount that does not apply.