Student loan calculator

How student loan repayment actually works

A student loan is an amortizing loan: you borrow a lump sum and pay it back in equal monthly installments over a fixed term, with interest charged on whatever balance is left. Your rate is quoted as an annual figure, but it’s applied monthly — divide it by twelve and that’s the rate added to your balance each month. At 6% on a $30,000 balance, the first month’s interest alone is about $150, so a level payment of roughly $333 puts the rest toward principal. As the balance falls, the interest slice of each payment shrinks and the principal slice grows, which is why the last few years of a loan clear the balance far faster than the first.

That’s the number this calculator solves for first: the single monthly payment that retires the loan exactly at the end of your term. From there it totals the interest you’ll pay, the total of all payments, and the date the loan disappears. Because it amortizes month by month rather than using a rough rule of thumb, the figures reflect how interest really accrues — and they update the instant you change a number.

Federal versus private loans

The biggest fork in the road is who lent you the money. Federal loans carry fixed rates set by Congress, don’t require a credit check for most undergraduates, and come wrapped in borrower protections: income-driven repayment, deferment and forbearance if you hit hard times, and forgiveness programs for public service and long-term repayment. Private loans from banks and online lenders price off your credit and income, can carry fixed or variable rates, and offer far fewer protections if your circumstances change. Rates and terms vary widely — federal undergraduate loans recently sat near 6–7%, while private rates can land anywhere from the low single digits to well into the teens depending on credit. Whatever your rate, plug it in above to see what it costs you over the life of the loan.

Standard, extended and income-driven plans

Federal borrowers choose how to repay. The standard plan spreads the balance over ten equal years — it’s the default modelled here and almost always the cheapest in total interest. Extended and graduated plans stretch the term out to 25 years or start payments low and step them up; both ease the monthly number but pile on interest. Income-driven plans cap your payment at a share of your discretionary income and can forgive whatever’s left after 20–25 years, which is a lifeline when the standard payment simply doesn’t fit your budget — though stretching the timeline usually means more interest along the way. This is general information, not a recommendation: the right plan depends on your income, your other goals, and how much certainty you want.

The extra-payment effect — and refinancing

The single most useful thing this tool shows is what a small increase does. Because any amount above the scheduled payment goes entirely to principal, the savings compound: you shrink the balance faster, which cuts future interest, which clears the loan sooner. The comparison table puts your standard payment beside $50 and $100 more and highlights the months and the dollars you’d save — often a couple of years and several hundred dollars on a typical balance, with no prepayment penalty on federal or most private loans. If you’re weighing extra payments against other priorities, our guide on whether to pay off student loans or invest walks through the trade-off, and our debt payoff planner compares loans against your other balances.

Refinancing is the other big lever. Swapping your loans for a new private loan at a lower rate can cut both your interest and your monthly payment — powerful if your credit and income have improved since you borrowed. The catch is real: refinancing federal loans into a private one permanently surrenders income-driven repayment, deferment, forbearance and any forgiveness you might qualify for, so the lower rate has to be worth giving up that safety net. Refinancing private loans carries far less risk. Run your current numbers above first, then read up on ways to pay off your student loans faster, and if you’re also chipping at plastic, the credit card payoff calculator shows where an extra dollar does the most good. This page is general information, not financial advice.