Student Loan Calculator
See your standard monthly payment and total interest — then find out how much you save by paying a little extra each month.
How this student loan calculator works
This calculator does two things. First, it shows your standard monthly payment — the fixed amount that pays off your balance plus interest over your chosen term, the same way the federal Standard Repayment Plan works on a 10-year (120-month) schedule. Second, and more usefully, it shows what happens when you pay a little extra each month.
The math behind extra payments is simple but powerful. Your loan accrues interest on the outstanding balance every month. When you pay more than the scheduled amount, the extra goes straight to principal, so the balance drops faster and less interest accrues in every month that follows. The result is a shorter payoff and a smaller total interest bill — often by thousands of dollars.
Standard vs. paying extra
On a $30,000 balance at 6% over the standard 10 years, the payment is about $333 a month and you'd pay roughly $9,970 in interest. Add just $100 a month and you pay the loan off almost three years early and save over $3,000 in interest. Because there is no prepayment penalty on federal student loans, every extra dollar works in your favor with no downside on the loan itself.
Key terms explained
Standard Repayment Plan. The default federal plan: fixed payments over 10 years. It costs more per month than longer or income-driven plans but pays the least total interest.
Principal vs. interest. Principal is the amount you borrowed; interest is the cost of borrowing it. Early in repayment, a large share of each payment goes to interest — which is exactly why extra principal payments early on save the most.
Extra payment. Any amount above your required payment. Tell your servicer to apply it to principal (not to "pay ahead" on the next bill) to get the full interest-saving effect.
What this calculator does not model
To stay clear and broadly accurate, this tool models a single fixed-rate loan on the standard schedule. It does not model income-driven repayment plans (IBR, PAYE, SAVE), loan forgiveness, interest capitalization after a grace period or deferment, or the differences between federal and private loans. Those depend heavily on your income, family size, and loan type. For decisions involving those programs, check the official details at studentaid.gov or speak with your loan servicer.
Deciding whether to throw extra money at loans or elsewhere? Run your real take-home pay to see what's affordable, and weigh high-rate debt against long-term retirement growth before committing.