Use this tool to estimate the standard payment on a fixed-rate student loan. Add an optional extra monthly amount to see the loan clear sooner and the interest it saves.
By the Personalloaner Editorial Team · Last updated 2026-09-16
How we get paid: if you apply through the link above, a lending partner may send us a referral fee. It never changes the rate you are offered or what we publish. We are not a lender and we do not process applications. The lowest rates are only available to the most qualified applicants. Full disclosure.
Enter your numbers and press Calculate. Nothing you type leaves your browser.
How we get paid: if you apply through the link above, a lending partner may send us a referral fee. It never changes the rate you are offered or what we publish. We are not a lender and we do not process applications. The lowest rates are only available to the most qualified applicants. Full disclosure.
How this calculator works
The tool estimates the standard payment on a fixed-rate student loan, then shows what a little extra each month changes.
Base payment: M = P * r * (1 + r)^n / ((1 + r)^n - 1).
With an extra amount E, the payment becomes M + E and the payoff time becomes n = -ln(1 - r * P / (M + E)) / ln(1 + r).
P = amount borrowed
r = monthly rate = annual rate / 12 / 100
n = number of monthly payments
Extra money goes straight to principal, so the payoff shortens and total interest falls. If the payment cannot cover the monthly interest, the balance never comes down.
Take the rate and term from your own agreement, since federal and private loans are not the same.
Common questions
What does an extra payment accomplish?
It cuts principal faster, so less interest accrues each month. The payoff arrives sooner and the total interest is lower.
Does it handle income-driven repayment?
It does not. The model assumes a fixed rate and equal payments. Income-driven plans reset the payment periodically and require a different model.
What term belongs in the box?
The term in your agreement, or the standard term you are weighing. Because terms differ, use the one that matches your loan.
Why is the balance stuck?
If the payment falls short of the monthly interest, nothing is left for principal. The tool then reports that the loan does not pay off.
