About this tool
Student Loan Repayment Calculator is a free, in-browser tool that computes the monthly payment, total interest and payoff date for student debt. It has two modes: enter a repayment term to get the required payment, or enter what you can pay each month to see how long the debt lasts.
The payment mode uses the amortization formula M = P·r/(1 − (1+r)⁻ⁿ); the time mode inverts it with n = −ln(1 − r·P/M)/ln(1+r), where r is the annual rate ÷ 12 ÷ 100. The payoff date is projected from today by that many months.
Rates and terms are fully user-entered, so it works for any country's loans — federal, private or bank. All math runs locally in your browser; your debt details are never uploaded.
Frequently asked questions
What do the two modes do?
'Solve payment' takes your target term in years and returns the fixed monthly payment needed to be debt-free by then. 'Solve time' takes the payment you can afford and returns how many months the loan will take, with the projected payoff date.
Why does it say my payment is too small?
If the monthly payment does not exceed the monthly interest (balance × rate ÷ 12 ÷ 100), the balance never shrinks and the payoff formula's logarithm has no solution — the loan would literally never end. Raise the payment above the monthly interest.
How exact is the total interest figure?
The tool simulates the schedule month by month with a trimmed final payment, so the total interest reflects an actual payoff rather than payment × months, which slightly overstates the last installment.
Does this work for loans outside the US?
Yes. Nothing is country-specific: you supply the balance, annual rate (compounded monthly) and term or payment, so it applies to student debt anywhere. Everything is computed locally in your browser.