Loans & Debt
Student Loan Repayment
Compare a 10-year and a 25-year repayment schedule, and see what an extra payment each month saves in time and interest.
What this means
On $35,000, the 10 yr standard plan runs $397 a month and $12,690 in interest. Stretching to 25 yr drops the payment by $161, but you'd pay $23,203 more in interest and carry the loan 15 yr longer.
Adding $100 a month to the standard payment finishes in 7 yr 5 mo instead of 10 yr and saves $3,504 in interest. Tell your servicer to apply the extra to principal, or it may just be counted toward next month's bill.
Federal loans also have income-driven repayment, where the payment is based on what you earn instead of what you owe. Those rules have been changing, and which plans you can choose depends on your loan type and when you borrowed, so this calculator doesn’t estimate them. Check your options on studentaid.gov or with your servicer. Private loans follow the lender’s own terms.
Build on it
These are estimates to help you think, not personalized legal, tax, or investment advice, and not a promise of any result.
This calculator compares three ways to repay the same student loan balance: a standard 10-year schedule, an extended 25-year schedule, and the 10-year payment plus whatever extra you can add each month. For each, it shows the monthly payment, how long it takes, and the total interest.
Why it matters: a longer schedule makes the payment smaller, and that can be exactly what a tight budget needs. It also keeps interest running for fifteen more years. Seeing both numbers together, and what a small extra payment does, helps you choose on purpose.
How to use it
Enter your balance and rate
Your total balance from your servicer's account page and the interest rate. With several loans at different rates, use a rough average weighted toward the bigger balances.
Add an extra amount if you can
Anything on top of the 10-year payment goes straight to principal. Even a small amount shortens the loan, and the calculator shows by how much.
Compare payment against total cost
The extended plan has the smallest payment and the largest total. The extra-payment plan has the largest payment and the smallest total. Pick the one you can keep up every month.
Behind the numbers
Why a longer schedule costs more
Interest is charged each month on whatever you still owe. Stretching the payments out keeps the balance higher for longer, so there are more months of interest on more money. The payment drops; the total climbs.
Extra payments and principal
Money you pay beyond the required amount should go to principal, which cuts every future month's interest. Servicers do not always apply it that way on their own. Tell yours the extra is for principal, and check that the next statement shows it.
Income-driven repayment exists
Federal loans also offer plans where the payment is based on your income and family size rather than your balance. Those rules have changed several times and depend on your loan type and when you borrowed, so this calculator does not estimate them. Check your options on studentaid.gov or with your servicer.
The math behind it
Each schedule is ordinary amortization. The level payment is the amount that, after a month of interest at your rate divided by twelve is added each month, brings the balance to zero in exactly 120 or 300 months. The extra-payment plan pays the 10-year amount plus your extra every month until the balance is gone, which happens sooner, so there are fewer months of interest.
Worked example
$35,000 at 6.5%: the standard plan is $397.42 a month and about $12,690 in interest over 10 years. The extended plan is $236.33 a month, $161 less, but about $35,893 in interest over 25 years. Paying $100 extra on the standard plan finishes in 7 yr 5 mo and saves about $3,504 in interest.
Pay the 10-year amount on any plan
If you choose a longer schedule for flexibility, you can usually still pay the 10-year amount when money allows. You keep the lower required payment as a safety net and pay far less interest when things are going well.
Common questions
Should I choose the standard or the extended plan?
The standard plan costs less in total. The extended plan has a smaller payment and costs more. If the standard payment fits your budget, it saves money; if it does not, a lower payment you can keep is better than a higher one you miss. Whether a 25-year schedule is open to you depends on your loans, so confirm with your servicer.
Is it worth paying extra on student loans?
Usually, once you have a starter emergency fund and are not leaving an employer retirement match on the table. Every extra dollar to principal saves interest at your loan's rate for the rest of the loan. The calculator shows the time and interest a given extra amount saves.
What about income-driven repayment or forgiveness?
Federal loans offer income-driven plans that set the payment from your income. The rules have been changing, so this calculator does not model them or any forgiveness program. Use the official tools on studentaid.gov or ask your servicer what you qualify for.
Does this work for private student loans?
The arithmetic does: any fixed-rate loan repaid in level payments follows the same schedule. Which repayment terms are available is up to your lender, so check your loan agreement.
Sources & references
Go deeper
The calculator gives you a number. The Debt Management Brick teaches you what to do with it, in plain English. And if you’re not sure where to start, the free BrickScore Assessment checks your whole foundation in about 5 minutes.
first the number, then the move