Estimate your monthly payments, total interest, and full repayment cost for one or more student loans.
Total Monthly Payment
Total Amount Paid
Total Interest Paid
$
%
$
Optional extra payment toward principal
Show Amortization Schedule
| Year | Opening Balance | Principal Paid | Interest Paid | Closing Balance |
|---|---|---|---|---|
| 1 | $30,000 | $2,258 | $1,739 | $27,742 |
| 2 | $27,742 | $2,397 | $1,599 | $25,344 |
| 3 | $25,344 | $2,545 | $1,451 | $22,799 |
| 4 | $22,799 | $2,702 | $1,294 | $20,097 |
| 5 | $20,097 | $2,869 | $1,128 | $17,228 |
| 6 | $17,228 | $3,046 | $951 | $14,182 |
| 7 | $14,182 | $3,234 | $763 | $10,948 |
| 8 | $10,948 | $3,433 | $563 | $7,515 |
| 9 | $7,515 | $3,645 | $352 | $3,870 |
| 10 | $3,870 | $3,870 | $127 | $0 |
Monthly payments are calculated using the standard amortization formula: the required payment that fully retires the loan over the chosen term at a fixed interest rate. Adding a monthly prepayment reduces your balance faster, shortening the effective loan term and cutting total interest paid.
The amortization schedule shows yearly rollups: how much of your payments went to principal vs. interest each year, and your remaining balance. All figures assume a fixed interest rate for the life of the loan.
A student loan is an installment loan. You borrow a fixed amount, interest builds on the balance, and you pay it back in equal monthly payments over a set term. Two features catch most new borrowers off guard:
Because of capitalization, making even small interest-only payments while you're still in school can keep the balance from quietly snowballing before repayment begins.
To calculate monthly student loan repayment, three inputs drive everything:
Our student payment calculator runs the math for you and handles several loans at once. Use it as an undergraduate student loan calculator for your subsidized and unsubsidized balances, or as a grad loan calculator for larger graduate-school debt — the summary tiles add up your combined monthly payment, total paid, and total interest. The optional prepayment field on each card shows how paying a little extra speeds up payoff.
A few things shape the rate you actually pay:
The average interest rate on student loans sits around 6% across federal debt. When you compare private offers and want to calculate interest rate on student loan costs accurately, look at the APR rather than the headline rate — the APR folds in fees, so it reflects what you'll really pay.
Student loan interest accrues daily, not monthly. To calculate your student loan interest for a given month, the shortcut is simple:
When you make a payment, that accrued interest is paid off first, and whatever is left chips away at your principal. If a payment doesn't even cover the interest, your balance grows instead of shrinks.
You can also run this backward to calculate the interest rate on a student loan: divide your monthly interest charge by your balance and multiply by 12. It's a handy check when a servicer's statement doesn't make the rate obvious.
The two differ mainly in scale and terms:
An undergraduate student loan calculator and a grad loan calculator use the same formula — the difference is the size of the numbers you plug in. Undergrads tend to model modest balances, while graduate and professional students model much larger ones with bigger monthly payments. Our calculator handles either without any special setup.
Private loans fill the gap when federal limits fall short of your school's cost of attendance. One of the most widely used is Sallie Mae's Smart Option Student Loan, which gives you three ways to handle payments while still in school:
A Sallie Mae Smart Option student loan calculator on the lender's site shows estimates for their loan, but running the same numbers through a neutral calculator lets you compare it head-to-head with other lenders. Before signing, compare the APR, check whether the rate is fixed or variable, and look at the deferment options in case of hardship later.
Most borrowers leave school with several loans — different federal disbursements across years, often at different rates, plus any private loans. A tool that lets you calculate education loan repayment across every balance at once shows you the full picture:
Seeing your full estimated monthly education loan repayment in one place is the first real step toward choosing a payoff strategy — whether that's a standard plan, an income-driven plan, or an aggressive extra-payment approach.
Refinancing swaps your existing loans for a new private loan, ideally at a lower rate or shorter term. Before you do it, weigh three things:
To estimate student loan refinance rate offers, get quotes from a few lenders, then model both scenarios in our calculator: your current loan in one card and the refinanced version in another. The difference in total interest shows the long-run savings side by side, before you weigh what you'd be giving up.
The biggest lever is making extra principal payments early, since interest builds on whatever balance remains. When you have several loans, two common approaches help you decide where extra money goes:
Use the prepayment field on each loan card to test both. Point the extra payment at whichever loan you'd tackle first, then compare the Total Interest Paid to see which ordering actually costs you less.
How does a student payment calculator work?
A student payment calculator takes your loan amount, annual interest rate, and term, then applies the standard amortization formula to find the fixed monthly payment that fully pays off the balance over that term. Enter more than one loan and it adds up your combined monthly payment and total interest across all your balances.
What is the average interest rate on student loans?
The average interest rate on student loans is around 6% across outstanding federal debt. Federal rates are set by Congress each year and fixed for the life of the loan, with graduate and PLUS loans priced higher than undergraduate loans. Private loan rates vary more widely and depend on your credit, your income, and whether the rate is fixed or variable.
How do I calculate my student loan interest for a given month?
Multiply your current balance by your annual interest rate, then divide by 12. Any payment you make covers that accrued interest first, and the remainder reduces your principal. If a payment is smaller than the interest charge, your balance actually grows instead of shrinking.
How is the monthly payment on a student loan estimated?
Your estimated monthly education loan repayment depends on three things: how much you borrowed, your interest rate, and your repayment term. A longer term lowers the monthly payment but raises the total interest you pay over time, while a shorter term does the opposite. Adjust the term in the calculator to see this trade-off play out instantly.
When does it make sense to refinance student loans?
Refinancing makes the strongest case when you have high-rate private loans, a solid credit score and stable income, and no plans to use federal programs like income-driven repayment or loan forgiveness. Refinancing federal loans into a private loan can lower your rate, but it permanently gives up those federal protections. To estimate your student loan refinance rate, get quotes from a few lenders and compare APR and flexibility — not just the headline rate.
How do extra payments affect my student loan payoff?
Extra payments go straight to principal, which lowers the interest you're charged every month afterward. Because interest builds on the remaining balance, extra payments made early have the biggest effect. Use the Monthly Prepayment field on each loan card to model it — the amortization table shows the shorter payoff timeline and the Total Interest Paid tile updates in real time.