Student Loan Calculator
See your monthly payment, total interest and payoff date, then add an extra monthly payment to find out how much interest and time you save. Free, no sign-up, runs entirely in your browser.
Extra payments are applied to principal every month, on top of the scheduled payment. Set extra to 0 to see the standard repayment plan.
Assumes a fixed rate and level monthly payments starting today. The payoff date is the month of the final payment under the plan with extra payments included.
How the student loan payment math works
Standard repayment amortizes your balance over a fixed term: payment = P × r ÷ (1 − (1 + r)−n), where r is the monthly rate (APR ÷ 12) and n is the number of months. On $30,000 at 6% over 10 years the payment is about $333.06, and the first payment sends roughly $150 to interest and $183 to principal. Interest accrues on the outstanding balance, so early payments are mostly interest and the balance falls slowly at first, then faster every year.
Extra payments attack the balance directly. Because interest is charged only on what you still owe, an extra $100 a month on the same loan saves roughly $3,050 of interest and cuts nearly 3 years off the term. The earlier you start, the bigger the effect, since each extra dollar avoids interest for every remaining month. The yearly table below shows exactly how the balance, principal and interest shift when you add the extra payment.
Using this as an education loan calculator
This page also works as a general education loan calculator for private student loans and refinanced loans, since the amortization math is identical to federal loans whenever the rate and term are fixed. Enter the balance and APR from your loan disclosure, pick the repayment term, and the results match what your servicer quotes for a level repayment plan. If you are comparing a federal loan against a private education loan refinance offer, run both through the calculator and compare total interest, not just the monthly payment, because a lower payment from a longer term usually means more interest overall. Note that income-driven repayment plans and variable-rate loans follow different rules and are outside what a fixed-term education loan calculator can model.
Year-by-year amortization summary
The table reflects your current inputs, including any extra monthly payment.
| Year | Principal paid | Interest paid | Balance at year end |
|---|
Frequently asked questions
How is my monthly student loan payment calculated?
Standard repayment uses the amortization formula: payment = balance x r / (1 - (1 + r)^-n), where r is the monthly interest rate (annual rate divided by 12) and n is the number of months. A $30,000 balance at 6% over 10 years gives a payment of about $333.06 per month. The payment stays fixed while the split between interest and principal shifts over time.
How much does an extra monthly payment save?
Extra payments go straight to principal, so every extra dollar avoids interest for the rest of the loan. On a $30,000 loan at 6% over 10 years, adding $100 a month saves roughly $3,300 in interest and pays the loan off about 3 years early. Enter any extra amount in this calculator to see your exact savings and new payoff date.
Can I use this as an education loan calculator for private loans?
Yes. The math is identical for federal and private education loans as long as the loan has a fixed rate and a fixed term, which covers most private student loans and refinancing offers. Just enter the balance, APR and term from your loan documents. It is not designed for variable-rate loans or income-driven repayment plans, where the payment changes over time.
What payoff date does this calculator assume?
The payoff date counts the required number of monthly payments starting from today, so a 10-year loan entered today shows a payoff month roughly 120 months from now. Your actual first payment date may differ by a few weeks depending on your servicer's schedule, which shifts the date slightly but not the payment or interest math.
Is this student loan calculator free?
Yes. It is completely free, requires no sign-up, and every calculation runs locally in your browser. Nothing you type is uploaded or stored.