Free calculator
Student Loan Calculator
This tool estimates the standard monthly payment on a fixed-rate education loan, then shows what an optional extra payment does to the payoff time and the interest bill.
The lowest rates are only available to the most qualified applicants.
Advertising disclosure: Loancalculated may receive a referral fee if you apply through the link above. That fee does not change the rate you are offered, and it does not change our content. We are not a lender. Read the full disclosure.
Enter your numbers and press Calculate. Nothing you type leaves your browser.
The lowest rates are only available to the most qualified applicants.
Advertising disclosure: Loancalculated may receive a referral fee if you apply through the link above. That fee does not change the rate you are offered, and it does not change our content. We are not a lender. Read the full disclosure.
How this calculator works
The base payment on a fixed-rate student loan follows the usual amortization relationship:
Payment = P × i ÷ (1 − (1 + i)−n)
Add an extra amount E and the new payment is payment + E, with payoff time n = −ln(1 − i × P ÷ (payment + E)) ÷ ln(1 + i).
- P — the amount borrowed
- i — the monthly rate (annual rate ÷ 1,200)
- n — the number of monthly payments
Extra money lands on principal, so it shortens the schedule and lowers the interest. If the payment cannot cover the monthly interest, the balance stops falling.
Use the rate and term from your own agreement; federal and private loans differ.